{"title":"PolarStar","description":"\u003cdiv style=\"background:#edfaf1;border-left:4px solid #27ae60;padding:12px 16px;border-radius:0 6px 6px 0;margin:0 0 16px;font-size:13px;\"\u003e\n\u003cstrong style=\"color:#1a6b3a;\"\u003ePolarStar — the HPA engine pioneer, and the platform that proved compressed air could run an AEG.\u003c\/strong\u003e Drop-in engines that replace a gearbox entirely, from the F2 to the mechanical Kythera.\u003c\/div\u003e\u003cp\u003ePolarStar were converting AEGs to run on air before most of the hobby had heard of HPA, and their poppet-valve engines are still a benchmark for tunability. The F2 and Fusion Engine swap a V2 or V3 gearbox for an electronically controlled air system, the JACK offers a simpler conversion, and the Kythera brings a mechanical HPA engine for players who want air power without the electronics. The Modular Regulator System feeds any of them a clean, adjustable supply.\u003c\/p\u003e\u003ch2 style=\"font-size:16px;color:#1B3A6B;margin:18px 0 8px;\"\u003eWhat we stock\u003c\/h2\u003e\u003cp\u003eWe carry the F2 and Fusion Engine GEN3 drop-in kits, the JACK conversion kit, the mechanical Kythera engine, the Modular Regulator System and spare F2 and JACK nozzles.\u003c\/p\u003e\u003cdiv style=\"background:#1B3A6B;color:#fff;padding:12px 16px;border-radius:6px;margin:18px 0 0;font-size:13px;\"\u003e\n\u003cstrong style=\"color:#fff;\"\u003e💡 Titan Forge Airsoft tip:\u003c\/strong\u003e Engine choice comes down to how much you want to tune — the F2 is endlessly adjustable, the Kythera keeps it simple. Compare them in our \u003ca href=\"\/collections\/hpa-engines\" style=\"color:#cdd6f4;\"\u003eHPA engines\u003c\/a\u003e.\u003c\/div\u003e","products":[{"product_id":"polarstar-jack-nozzle-cyma-mp5k-pdw-21","title":"POLARSTAR JACK Nozzle","description":"\u003ch1\u003ePolarStar JACK Nozzles\u003c\/h1\u003e\n\u003cp\u003e\u003cstrong\u003eDial in correct feeding, air seal, and platform compatibility for your PolarStar JACK engine.\u003c\/strong\u003e PolarStar JACK Nozzles are designed to match specific replica platforms by nozzle length, helping ensure reliable BB feeding, correct hop-up alignment, and consistent performance from your HPA build.\u003c\/p\u003e\n\u003ch2\u003eWhy Nozzle Selection Matters\u003c\/h2\u003e\n\u003cp\u003eDifferent airsoft platforms – and even different manufacturers making the same platform – can require different nozzle lengths. This is because gearbox shell dimensions, hop-up positioning, and internal tolerances can vary between brands. Using the correct nozzle is essential for proper feeding reliability, air seal, and consistent FPS output.\u003c\/p\u003e\n\u003ch2\u003ePolarStar Numbered Nozzle System\u003c\/h2\u003e\n\u003cp\u003ePolarStar uses a numbered nozzle system for cylinder conversion engines rather than naming nozzles after a specific rifle model. Once you determine the correct nozzle number for your platform, that number is generally universal across PolarStar engines that use the numbered nozzle system, excluding some model-specific Kythera systems.\u003c\/p\u003e\n\u003ch2\u003eJACK Nozzle Compatibility Guide\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eNozzle Number\u003c\/th\u003e\n\u003cth\u003eMost Commonly Used With\u003c\/th\u003e\n\u003cth\u003eTip Length (Inches)\u003c\/th\u003e\n\u003cth\u003eOAL (Inches)\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e1\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eTM M4\/M16, A\u0026amp;K PKM, TM MP5 A\/SD, ICS MP5 A\/SD, G\u0026amp;G KAC SR-25E2\u003c\/td\u003e\n\u003ctd\u003e0.8245\u003c\/td\u003e\n\u003ctd\u003e1.677\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e2\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCYMA AK, CYMA MP5 A\/SD, G\u0026amp;G UMP\u003c\/td\u003e\n\u003ctd\u003e0.8625\u003c\/td\u003e\n\u003ctd\u003e1.715\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e3\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCA M249\/MK46, A\u0026amp;K M249\/MK46\u003c\/td\u003e\n\u003ctd\u003e0.8095\u003c\/td\u003e\n\u003ctd\u003e1.662\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e4\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eG\u0026amp;G GR-25\u003c\/td\u003e\n\u003ctd\u003e1.4505\u003c\/td\u003e\n\u003ctd\u003e2.303\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e5\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eA\u0026amp;K SR-25, JG SR-25, ICS SIG 550\/551\/552\u003c\/td\u003e\n\u003ctd\u003e0.9635\u003c\/td\u003e\n\u003ctd\u003e1.816\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e6\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eKA FAL, TM MP5K, A\u0026amp;K M240\u003c\/td\u003e\n\u003ctd\u003e0.8945\u003c\/td\u003e\n\u003ctd\u003e1.747\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e7\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ePTS MASADA, CA SCAR-L\u003c\/td\u003e\n\u003ctd\u003e1.1345\u003c\/td\u003e\n\u003ctd\u003e1.987\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e8\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eVFC SCAR-H\u003c\/td\u003e\n\u003ctd\u003e1.5075\u003c\/td\u003e\n\u003ctd\u003e2.36\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e9\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eEF\/S\u0026amp;T TAR-21 COMP\u003c\/td\u003e\n\u003ctd\u003e0.8765\u003c\/td\u003e\n\u003ctd\u003e1.729\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e10\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eEF ARX160 ELITE\u003c\/td\u003e\n\u003ctd\u003e1.4865\u003c\/td\u003e\n\u003ctd\u003e2.339\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e11\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCA KAC LMG, VFC MP5 A\/SD\u003c\/td\u003e\n\u003ctd\u003e0.7475\u003c\/td\u003e\n\u003ctd\u003e1.6\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e12\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eLCT AK-47\/74\/M, LCT VSS\/AS VAL\u003c\/td\u003e\n\u003ctd\u003e0.8355\u003c\/td\u003e\n\u003ctd\u003e1.688\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e13\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eA\u0026amp;K MASADA\/ACR\u003c\/td\u003e\n\u003ctd\u003e1.3465\u003c\/td\u003e\n\u003ctd\u003e2.199\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e14\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eKA CZ 805 BREN, CG M249 Featherweight, A\u0026amp;K M60\u003c\/td\u003e\n\u003ctd\u003e1.3895\u003c\/td\u003e\n\u003ctd\u003e2.242\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e15\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eEF\/ARES G36KV\/CV, JG G36\u003c\/td\u003e\n\u003ctd\u003e1.0545\u003c\/td\u003e\n\u003ctd\u003e1.907\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e16\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eEF\/S\u0026amp;T G36C\u003c\/td\u003e\n\u003ctd\u003e1.0415\u003c\/td\u003e\n\u003ctd\u003e1.894\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e17\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCA AUG\u003c\/td\u003e\n\u003ctd\u003e1.0045\u003c\/td\u003e\n\u003ctd\u003e1.857\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e18\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eG\u0026amp;G MP5 A\/SD\u003c\/td\u003e\n\u003ctd\u003e0.795\u003c\/td\u003e\n\u003ctd\u003e1.647\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e19\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eVFC\/ECHO1 XCR\u003c\/td\u003e\n\u003ctd\u003e1.227\u003c\/td\u003e\n\u003ctd\u003e2.079\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e20\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCA G36, CYMA SR-25\u003c\/td\u003e\n\u003ctd\u003e1.026\u003c\/td\u003e\n\u003ctd\u003e1.8785\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e21\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eElite Force\/CYMA MP5K, CA SA58\u003c\/td\u003e\n\u003ctd\u003e0.923\u003c\/td\u003e\n\u003ctd\u003e1.771\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMP7\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ePolarStar MP7 applications\u003c\/td\u003e\n\u003ctd\u003ePlatform specific\u003c\/td\u003e\n\u003ctd\u003ePlatform specific\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch2\u003eMeasurement Guidance\u003c\/h2\u003e\n\u003cp\u003ePolarStar notes that if your replica is not listed in their compatibility database, nozzle length can be calculated by measuring the original gearbox and nozzle. For JACK centreline nozzles, the formula is:\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eTIP = F + B - (A\/2) - .0875\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe measured tip length should be within \u003cstrong\u003e+\/- 0.010\"\u003c\/strong\u003e of an existing production nozzle to be considered compatible. If it falls outside that range, a production nozzle may not currently exist for that platform.\u003c\/p\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eGenuine PolarStar replacement component\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eDesigned specifically for PolarStar JACK engines\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003ePlatform-specific feeding optimisation\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eSupports consistent FPS performance\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eImproves air seal and air efficiency\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eEssential for correct HPA engine installation\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eNumbered system shared across compatible PolarStar engines\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWhat’s Included\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e1 x PolarStar JACK Nozzle (selected variant)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eImportant Information\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Always confirm the correct nozzle before purchase. The platforms listed are the most commonly used applications, but fitment may vary between manufacturers.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eInstallation:\u003c\/strong\u003e Recommended during engine installation or servicing.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eUse:\u003c\/strong\u003e Intended for airsoft use only.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eChoosing the correct nozzle is essential for feeding reliability, air efficiency, and consistent performance\u003c\/strong\u003e — an important final step in any PolarStar JACK build.\u003c\/p\u003e","brand":"Polarstar","offers":[{"title":"#01","offer_id":55505178952056,"sku":"42016983","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#02","offer_id":55505178984824,"sku":"52080025","price":22.95,"currency_code":"GBP","in_stock":false},{"title":"#03","offer_id":55505179017592,"sku":"90503096","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#04","offer_id":55505179050360,"sku":"12765172","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#05","offer_id":55505179083128,"sku":"83356129","price":22.95,"currency_code":"GBP","in_stock":false},{"title":"#06","offer_id":55505179115896,"sku":"54011757","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#07","offer_id":55505179148664,"sku":"89290280","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#08","offer_id":55505179181432,"sku":"58061700","price":22.95,"currency_code":"GBP","in_stock":false},{"title":"#09","offer_id":55505179214200,"sku":"92318991","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#10","offer_id":55505179246968,"sku":"26991595","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#11","offer_id":55505179279736,"sku":"49085122","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#12","offer_id":55505179312504,"sku":"80243638","price":22.95,"currency_code":"GBP","in_stock":false},{"title":"#13","offer_id":55505179345272,"sku":"86459813","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#14","offer_id":55505179378040,"sku":"73857768","price":22.95,"currency_code":"GBP","in_stock":false},{"title":"#15","offer_id":55505179410808,"sku":"30520058","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#16","offer_id":55505179443576,"sku":"96220975","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#17","offer_id":55505179476344,"sku":"62177708","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#18","offer_id":55505179509112,"sku":"24462679","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#19","offer_id":55505179541880,"sku":"53177935","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#20","offer_id":55505179574648,"sku":"90445902","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"#21","offer_id":55505179607416,"sku":"70298814","price":22.95,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0562\/8097\/3450\/files\/JackNozzle_3tKZ2QD-Photoroom.jpg?v=1764255283"},{"product_id":"polarstar-jack-hpa-conversion-kit-v2-m4m16","title":"PolarStar JACK HPA Conversion Kit","description":"\u003cdiv class=\"callout-info\" style=\"background:#ebf2fa;border-left:4px solid #1B3A6B;padding:12px 16px;border-radius:0 6px 6px 0;margin:0 0 16px;font-size:13px;\"\u003e\n\u003cstrong style=\"color:#1B3A6B;\"\u003e🔧 Planning an HPA conversion?\u003c\/strong\u003e Before ordering, read our \u003ca href=\"\/pages\/how-to-convert-your-m4-aeg-to-hpa-uk\" style=\"color:#1B3A6B;font-weight:bold;\"\u003estep-by-step M4 AEG to HPA conversion guide\u003c\/a\u003e — it covers compatibility, what the install involves, what else you need, and the upgrade path after fitting.\u003c\/div\u003e\u003ch1\u003ePolarStar JACK HPA Conversion Kit\u003c\/h1\u003e\n\u003cp\u003e\u003cstrong\u003eReliable HPA performance with simple tuning and proven durability.\u003c\/strong\u003e The PolarStar JACK is one of the most popular drop-in HPA conversion engines in airsoft, offering consistent shot performance, reduced mechanical wear, and straightforward tuning. Designed as a replacement for traditional gearbox internals, the JACK delivers fast trigger response and dependable operation for both casual players and experienced builders.\u003c\/p\u003e\n\u003ch2\u003eOpen Bolt Single Solenoid Design\u003c\/h2\u003e\n\u003cp\u003eThe JACK utilises a \u003cstrong\u003esingle-solenoid open bolt system\u003c\/strong\u003e, making it simple to configure while still providing excellent air efficiency and consistent FPS output. This streamlined design reduces complexity compared to dual-solenoid systems while maintaining strong performance.\u003c\/p\u003e\n\u003ch2\u003eConsistent Performance \u0026amp; Reliability\u003c\/h2\u003e\n\u003cp\u003eBy eliminating gears, pistons, and springs, the JACK reduces mechanical stress inside the platform. This results in smoother cycling, improved reliability, and reduced maintenance requirements during extended gameplay.\u003c\/p\u003e\n\u003ch2\u003eDrop-In Conversion Platform\u003c\/h2\u003e\n\u003cp\u003eThe JACK is engineered as a drop-in engine for compatible gearboxes, allowing players to convert AEG platforms to HPA with minimal modification (platform dependent).\u003c\/p\u003e\n\u003ch2\u003eAvailable Platform Variants\u003c\/h2\u003e\n\u003cp\u003eThis listing combines multiple PolarStar JACK conversion kits. Please select the correct version before purchase:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eAres Amoeba EFCS \/ APS ESE\u003c\/li\u003e\n\u003cli\u003eAres M4\u003c\/li\u003e\n\u003cli\u003eKAC LMG\u003c\/li\u003e\n\u003cli\u003eM249\u003c\/li\u003e\n\u003cli\u003eM60\u003c\/li\u003e\n\u003cli\u003eS\u0026amp;T TAR-21\u003c\/li\u003e\n\u003cli\u003eVersion 2 M4 \/ M16\u003c\/li\u003e\n\u003cli\u003eVersion 3 AK\u003c\/li\u003e\n\u003cli\u003eVFC HK417\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003ePolarStar JACK HPA engine\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eSingle-solenoid open bolt system\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eConsistent FPS output\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eAdjustable dwell and rate of fire\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eReduced gearbox wear\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eReliable and efficient air usage\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eMultiple platform-specific variants available\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003cth\u003eDetails\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eManufacturer\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ePolarStar\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eEngine Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eSingle-Solenoid Open Bolt HPA Engine\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003ePower Source\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eHPA (External Tank \u0026amp; Regulator Required)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eGearbox Compatibility\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ePlatform Specific (Variant Dependent)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTuning\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eDwell \u0026amp; Rate of Fire Adjustment\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch2\u003eWhat’s Included\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003ePolarStar JACK HPA Engine (platform specific)\u003c\/li\u003e\n\u003cli\u003eWiring harness\u003c\/li\u003e\n\u003cli\u003eInstallation components (variant dependent)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eImportant Information\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eInstallation:\u003c\/strong\u003e Professional installation is recommended for HPA engine conversions.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Ensure correct gearbox \/ platform variant is selected before purchase.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHPA System:\u003c\/strong\u003e Requires external HPA tank, regulator, and line (sold separately).\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eUse:\u003c\/strong\u003e Intended for airsoft use only.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eSimple tuning, proven performance, and dependable reliability\u003c\/strong\u003e — the PolarStar JACK remains one of the best entry points into HPA engine conversions.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch2\u003ePolarStar Engine Comparison Guide\u003c\/h2\u003e\n\n\u003cp\u003eNot sure which PolarStar engine is right for your build? Use this quick comparison to understand the key differences between the JACK, F2, and Kythera systems.\u003c\/p\u003e\n\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eFeature\u003c\/th\u003e\n\u003cth\u003ePolarStar JACK\u003c\/th\u003e\n\u003cth\u003ePolarStar F2\u003c\/th\u003e\n\u003cth\u003ePolarStar Kythera\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\n\u003ctbody\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eEngine Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eSingle Solenoid\u003c\/td\u003e\n\u003ctd\u003eDual Solenoid\u003c\/td\u003e\n\u003ctd\u003eMechanical Closed-Bolt\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eElectronics Required\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eYes (FCU \u0026amp; Battery)\u003c\/td\u003e\n\u003ctd\u003eYes (FCU \u0026amp; Battery)\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTrigger Feel\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eElectronic\u003c\/td\u003e\n\u003ctd\u003eElectronic\u003c\/td\u003e\n\u003ctd\u003eMechanical \/ Realistic\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTuning Capability\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eGood\u003c\/td\u003e\n\u003ctd\u003eAdvanced \/ Independent Nozzle \u0026amp; Poppet Control\u003c\/td\u003e\n\u003ctd\u003eMechanical Adjustments Only\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAir Efficiency\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eVery Good\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eRate of Fire Potential\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eHigh\u003c\/td\u003e\n\u003ctd\u003eVery High\u003c\/td\u003e\n\u003ctd\u003eSemi-Focused\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBest For\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eAffordable HPA conversions\u003c\/td\u003e\n\u003ctd\u003eHigh performance competitive builds\u003c\/td\u003e\n\u003ctd\u003eRealistic \/ DMR \/ Battery-free builds\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eInstallation Complexity\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eModerate\u003c\/td\u003e\n\u003ctd\u003eModerate\u003c\/td\u003e\n\u003ctd\u003eModerate\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eReliability\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eQuick Buyer Advice\u003c\/h3\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose JACK\u003c\/strong\u003e if you want a reliable and cost-effective entry into HPA.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose F2\u003c\/strong\u003e if you want maximum tuning control, performance, and competitive capability.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose Kythera\u003c\/strong\u003e if you want a battery-free mechanical system with realistic trigger feel.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Polarstar","offers":[{"title":"Ares Amoeba EFCS \/ APS ESE","offer_id":55504393568632,"sku":"95483115","price":344.95,"currency_code":"GBP","in_stock":true},{"title":"Ares M4","offer_id":55504393601400,"sku":"12268996","price":349.95,"currency_code":"GBP","in_stock":false},{"title":"KAC LMG","offer_id":55504393634168,"sku":"28031986","price":324.95,"currency_code":"GBP","in_stock":false},{"title":"M249","offer_id":55504393666936,"sku":"97293055","price":324.95,"currency_code":"GBP","in_stock":true},{"title":"M60","offer_id":55504393699704,"sku":"73148567","price":329.95,"currency_code":"GBP","in_stock":false},{"title":"S\u0026T TAR-21","offer_id":55504393732472,"sku":"27463714","price":334.95,"currency_code":"GBP","in_stock":false},{"title":"Version 2 M4 \/ M16","offer_id":55504393765240,"sku":"65280674","price":324.95,"currency_code":"GBP","in_stock":true},{"title":"Version 3 AK","offer_id":55504393798008,"sku":"60174322","price":329.95,"currency_code":"GBP","in_stock":true},{"title":"VFC HK417","offer_id":55504393830776,"sku":"32444364","price":339.95,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0562\/8097\/3450\/files\/JACK_Scaled-Photoroom.jpg?v=1773834301"},{"product_id":"polarstar-f2-drop-in-conversion-kit","title":"Polarstar F2 Drop-in Conversion Kit","description":"\u003ch1\u003ePolarStar F2 Drop-In HPA Conversion Kit\u003c\/h1\u003e\n\u003cp\u003e\u003cstrong\u003eLegendary dual-solenoid HPA performance.\u003c\/strong\u003e The PolarStar F2 Drop-In Conversion Kit is designed for players and builders who demand maximum control, efficiency, and consistency from their airsoft platform. Engineered as a true drop-in HPA engine, the F2 replaces traditional gearbox internals to deliver faster trigger response, improved reliability, and fully tunable performance.\u003c\/p\u003e\n\u003ch2\u003eDual-Solenoid Closed Bolt System\u003c\/h2\u003e\n\u003cp\u003eThe PolarStar F2 features an advanced \u003cstrong\u003edual-solenoid design\u003c\/strong\u003e, allowing independent control of nozzle timing and poppet dwell. This enables precise tuning for air efficiency, rate of fire, and shot consistency — making it one of the most versatile HPA engines available.\u003c\/p\u003e\n\u003ch2\u003eConsistent Shot Performance\u003c\/h2\u003e\n\u003cp\u003eBy removing traditional gearbox gears, pistons, and springs, the F2 dramatically reduces mechanical stress while delivering consistent FPS output and smooth cycling. This results in improved reliability during high-intensity gameplay.\u003c\/p\u003e\n\u003ch2\u003eDrop-In Conversion Simplicity\u003c\/h2\u003e\n\u003cp\u003eDesigned as a drop-in system for compatible platforms, the F2 simplifies the HPA conversion process while still offering deep tuning potential for advanced users.\u003c\/p\u003e\n\u003ch2\u003eAvailable Variants\u003c\/h2\u003e\n\u003cp\u003eThis listing combines multiple platform-specific F2 conversion kits. Please select the correct option before purchase:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eM249 Version\u003c\/strong\u003e – Designed for compatible M249 gearbox platforms\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eV2 Version\u003c\/strong\u003e – Designed for M4 \/ M16 style Version 2 gearboxes\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eV3 Version\u003c\/strong\u003e – Designed for AK style Version 3 gearboxes\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003ePolarStar F2 dual-solenoid HPA engine\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eIndependent poppet and nozzle control\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eHigh air efficiency design\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eConsistent FPS performance\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eAdjustable rate of fire and dwell settings\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eReduced mechanical wear compared to AEG systems\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eTrue drop-in conversion platform (variant dependent)\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003cth\u003eDetails\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eManufacturer\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ePolarStar\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eEngine Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eDual-Solenoid Closed Bolt HPA Engine\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003ePower Source\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eHPA (External Tank \u0026amp; Regulator Required)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eGearbox Compatibility\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eM249 \/ Version 2 \/ Version 3 (Variant Dependent)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTuning\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eIndependent Nozzle \u0026amp; Poppet Adjustment\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch2\u003eWhat’s Included\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003ePolarStar F2 HPA Engine (platform specific)\u003c\/li\u003e\n\u003cli\u003eWiring harness\u003c\/li\u003e\n\u003cli\u003eInstallation components (variant dependent)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eImportant Information\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eInstallation:\u003c\/strong\u003e Professional installation is recommended for HPA conversions.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Ensure gearbox version and platform compatibility before purchase.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHPA System:\u003c\/strong\u003e Requires external HPA tank, regulator, and line (sold separately).\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eUse:\u003c\/strong\u003e Intended for airsoft use only.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eUltimate control, precision tuning, and proven HPA performance\u003c\/strong\u003e — the PolarStar F2 remains one of the most respected conversion engines in airsoft.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch2\u003ePolarStar Engine Comparison Guide\u003c\/h2\u003e\n\n\u003cp\u003eNot sure which PolarStar engine is right for your build? Use this quick comparison to understand the key differences between the JACK, F2, and Kythera systems.\u003c\/p\u003e\n\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eFeature\u003c\/th\u003e\n\u003cth\u003ePolarStar JACK\u003c\/th\u003e\n\u003cth\u003ePolarStar F2\u003c\/th\u003e\n\u003cth\u003ePolarStar Kythera\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\n\u003ctbody\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eEngine Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eSingle Solenoid\u003c\/td\u003e\n\u003ctd\u003eDual Solenoid\u003c\/td\u003e\n\u003ctd\u003eMechanical Closed-Bolt\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eElectronics Required\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eYes (FCU \u0026amp; Battery)\u003c\/td\u003e\n\u003ctd\u003eYes (FCU \u0026amp; Battery)\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTrigger Feel\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eElectronic\u003c\/td\u003e\n\u003ctd\u003eElectronic\u003c\/td\u003e\n\u003ctd\u003eMechanical \/ Realistic\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTuning Capability\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eGood\u003c\/td\u003e\n\u003ctd\u003eAdvanced \/ Independent Nozzle \u0026amp; Poppet Control\u003c\/td\u003e\n\u003ctd\u003eMechanical Adjustments Only\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAir Efficiency\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eVery Good\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eRate of Fire Potential\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eHigh\u003c\/td\u003e\n\u003ctd\u003eVery High\u003c\/td\u003e\n\u003ctd\u003eSemi-Focused\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBest For\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eAffordable HPA conversions\u003c\/td\u003e\n\u003ctd\u003eHigh performance competitive builds\u003c\/td\u003e\n\u003ctd\u003eRealistic \/ DMR \/ Battery-free builds\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eInstallation Complexity\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eModerate\u003c\/td\u003e\n\u003ctd\u003eModerate\u003c\/td\u003e\n\u003ctd\u003eModerate\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eReliability\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003c\/tr\u003e\n\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eQuick Buyer Advice\u003c\/h3\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose JACK\u003c\/strong\u003e if you want a reliable and cost-effective entry into HPA.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose F2\u003c\/strong\u003e if you want maximum tuning control, performance, and competitive capability.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose Kythera\u003c\/strong\u003e if you want a battery-free mechanical system with realistic trigger feel.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Polarstar","offers":[{"title":"M249","offer_id":55504259613048,"sku":"42106512","price":409.95,"currency_code":"GBP","in_stock":true},{"title":"M4 \/ M16","offer_id":55504259645816,"sku":"50507417","price":409.95,"currency_code":"GBP","in_stock":false},{"title":"V3 - AK","offer_id":55504259678584,"sku":"37492912","price":409.95,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0562\/8097\/3450\/files\/F2-M249.jpg?v=1773831617"},{"product_id":"polarstar-kythera-mechanical-hpa-engine","title":"Polarstar Kythera Mechanical HPA Engine","description":"\u003cdiv class=\"callout-info\" style=\"background:#ebf2fa;border-left:4px solid #1B3A6B;padding:12px 16px;border-radius:0 6px 6px 0;margin:0 0 16px;font-size:13px;\"\u003e\n\u003cstrong style=\"color:#1B3A6B;\"\u003e🔧 Planning an HPA conversion?\u003c\/strong\u003e Before ordering, read our \u003ca href=\"\/pages\/how-to-convert-your-m4-aeg-to-hpa-uk\" style=\"color:#1B3A6B;font-weight:bold;\"\u003estep-by-step M4 AEG to HPA conversion guide\u003c\/a\u003e — it covers compatibility, what the install involves, what else you need, and the upgrade path after fitting.\u003c\/div\u003e\u003ch1\u003ePolarStar Kythera Mechanical HPA Engine\u003c\/h1\u003e\n\u003cp\u003e\u003cstrong\u003ePure mechanical HPA performance — no battery, no electronics.\u003c\/strong\u003e The PolarStar Kythera is a fully mechanical HPA engine designed for players who want reliable, consistent performance without relying on electronic trigger systems. Built around a closed-bolt design, the Kythera delivers realistic trigger feel, excellent air efficiency, and dependable operation in all weather conditions.\u003c\/p\u003e\n\u003ch2\u003eMechanical Closed-Bolt System\u003c\/h2\u003e\n\u003cp\u003eUnlike electronic HPA engines, the Kythera operates using a \u003cstrong\u003efully mechanical trigger and valve system\u003c\/strong\u003e. This removes the need for batteries, wiring, or FCUs while still providing consistent FPS output and efficient air usage.\u003c\/p\u003e\n\u003ch2\u003eRealistic Trigger Feel\u003c\/h2\u003e\n\u003cp\u003eThe mechanical trigger system provides a more traditional and tactile shooting experience, making it popular with players who prefer a realistic firing feel or want to build semi-only DMR and sniper platforms.\u003c\/p\u003e\n\u003ch2\u003eReliable \u0026amp; Efficient Performance\u003c\/h2\u003e\n\u003cp\u003eThe Kythera’s simplified design reduces electrical components and moving parts, improving long-term reliability while maintaining strong air efficiency. This makes it an excellent choice for players who prioritise durability and simplicity.\u003c\/p\u003e\n\u003ch2\u003eAvailable Variants\u003c\/h2\u003e\n\u003cp\u003eThis listing includes multiple Kythera configurations. Please select the correct version before purchase:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eVersion 2\u003c\/strong\u003e – Compatible with M4 \/ M16 style platforms\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVersion 2.5\u003c\/strong\u003e – Designed for JG SR-25 gearbox platforms\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVersion 3\u003c\/strong\u003e – Compatible with AK style platforms\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eFully mechanical HPA engine\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eNo battery or electronics required\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eClosed-bolt firing system\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eRealistic trigger feel\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eExcellent air efficiency\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eReduced electrical failure points\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eIdeal for DMR and semi-locked builds\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eMultiple gearbox variants available\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003cth\u003eDetails\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eManufacturer\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ePolarStar\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eEngine Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eMechanical Closed-Bolt HPA Engine\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003ePower Source\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eHPA (External Tank \u0026amp; Regulator Required)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eElectronics\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eNone Required\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eGearbox Compatibility\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eV2 \/ V2.5 \/ V3 (Variant Dependent)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch2\u003eWhat’s Included\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003ePolarStar Kythera HPA Engine (variant dependent)\u003c\/li\u003e\n\u003cli\u003eInstallation components\u003cbr\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eImportant Information\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eInstallation:\u003c\/strong\u003e Professional installation is recommended for HPA engine conversions.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Ensure correct gearbox version is selected before purchase.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHPA System:\u003c\/strong\u003e Requires external HPA tank, regulator, and line (sold separately).\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eUse:\u003c\/strong\u003e Intended for airsoft use only.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eMechanical simplicity, reliable performance, and realistic trigger control\u003c\/strong\u003e — the PolarStar Kythera is the ideal HPA engine for players who want performance without electronics.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch2\u003ePolarStar Engine Comparison Guide\u003c\/h2\u003e\n\u003cp\u003eNot sure which PolarStar engine is right for your build? Use this quick comparison to understand the key differences between the JACK, F2, and Kythera systems.\u003c\/p\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eFeature\u003c\/th\u003e\n\u003cth\u003ePolarStar JACK\u003c\/th\u003e\n\u003cth\u003ePolarStar F2\u003c\/th\u003e\n\u003cth\u003ePolarStar Kythera\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eEngine Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eSingle Solenoid\u003c\/td\u003e\n\u003ctd\u003eDual Solenoid\u003c\/td\u003e\n\u003ctd\u003eMechanical Closed-Bolt\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eElectronics Required\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eYes (FCU \u0026amp; Battery)\u003c\/td\u003e\n\u003ctd\u003eYes (FCU \u0026amp; Battery)\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTrigger Feel\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eElectronic\u003c\/td\u003e\n\u003ctd\u003eElectronic\u003c\/td\u003e\n\u003ctd\u003eMechanical \/ Realistic\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTuning Capability\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eGood\u003c\/td\u003e\n\u003ctd\u003eAdvanced \/ Independent Nozzle \u0026amp; Poppet Control\u003c\/td\u003e\n\u003ctd\u003eMechanical Adjustments Only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAir Efficiency\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eVery Good\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eRate of Fire Potential\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eHigh\u003c\/td\u003e\n\u003ctd\u003eVery High\u003c\/td\u003e\n\u003ctd\u003eSemi-Focused\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBest For\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eAffordable HPA conversions\u003c\/td\u003e\n\u003ctd\u003eHigh performance competitive builds\u003c\/td\u003e\n\u003ctd\u003eRealistic \/ DMR \/ Battery-free builds\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eInstallation Complexity\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eModerate\u003c\/td\u003e\n\u003ctd\u003eModerate\u003c\/td\u003e\n\u003ctd\u003eModerate\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eReliability\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003eQuick Buyer Advice\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose JACK\u003c\/strong\u003e if you want a reliable and cost-effective entry into HPA.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose F2\u003c\/strong\u003e if you want maximum tuning control, performance, and competitive capability.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose Kythera\u003c\/strong\u003e if you want a battery-free mechanical system with realistic trigger feel.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Polarstar","offers":[{"title":"V2 (M4\/M16)","offer_id":55504523035000,"sku":"42889148","price":314.95,"currency_code":"GBP","in_stock":true},{"title":"V2.5 (JG SR-25)","offer_id":55504523067768,"sku":"26851963","price":279.95,"currency_code":"GBP","in_stock":false},{"title":"V3 (AK)","offer_id":55504523100536,"sku":"74009696","price":314.95,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0562\/8097\/3450\/files\/IMG_1705_modified_6000a7ac-33f4-4a33-abab-48576a2b1cf3.jpg?v=1773835316"},{"product_id":"polarstar-f2-nozzle","title":"POLARSTAR F2 Nozzle","description":"\u003ch1\u003ePolarStar F2 Replacement Nozzles\u003c\/h1\u003e\n\n\u003cp\u003e\u003cstrong\u003eFine-tune compatibility and feeding performance for your PolarStar F2 engine.\u003c\/strong\u003e PolarStar F2 Replacement Nozzles are designed to ensure correct air seal, feeding reliability, and platform compatibility when installing or upgrading an F2 HPA engine. Each nozzle variant is engineered for specific rifle platforms, making proper selection essential for optimal performance.\u003c\/p\u003e\n\n\u003ch2\u003ePlatform-Specific Fitment\u003c\/h2\u003e\n\u003cp\u003eDifferent airsoft platforms require different nozzle lengths and geometries. 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M240\u003c\/td\u003e\n\u003ctd\u003e1.2745\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e7\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ePTS MASADA, CA SCAR-L\u003c\/td\u003e\n\u003ctd\u003e1.514\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e8\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eVFC SCAR-H\u003c\/td\u003e\n\u003ctd\u003e1.8875\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e9\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eEF\/S\u0026amp;T TAR-21 COMP\u003c\/td\u003e\n\u003ctd\u003e1.2565\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e10\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eEF ARX160 ELITE\u003c\/td\u003e\n\u003ctd\u003e1.866\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e11\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCA KAC LMG, VFC MP5 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installation\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhat’s Included\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e1 × PolarStar F2 Replacement Nozzle (Selected Variant)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eImportant Information\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Always confirm correct nozzle selection before purchase. Incorrect nozzle choice may cause feeding issues or inconsistent performance.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eInstallation:\u003c\/strong\u003e Recommended during engine installation or maintenance.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eUse:\u003c\/strong\u003e Intended for airsoft use only.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eSelecting the correct nozzle ensures optimal feeding reliability, air efficiency, and shot consistency.\u003c\/strong\u003e\u003c\/p\u003e","brand":"Polarstar","offers":[{"title":"1. TM M4\/M16 - A\u0026K PKM - TM MP5 A\/SD - ICS MP5 A\/SD - G\u0026G KAC SR-25E2","offer_id":55504540434808,"sku":"11735056","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"2. CYMA AK - CYMA MP5 A\/SD - G\u0026G UMP","offer_id":55504540467576,"sku":"37646546","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"3. CA M249\/MK46 - A\u0026K M249\/MK46","offer_id":55504540500344,"sku":"26848458","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"4. G\u0026G GR-25","offer_id":55504540533112,"sku":"63674798","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"5. A\u0026K SR-25 -JG SR-25 - ICS SIG 550\/551\/552","offer_id":55504540565880,"sku":"56444323","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"6. KA FAL - TM MP5K -A\u0026K M240","offer_id":55504540598648,"sku":"19259976","price":24.95,"currency_code":"GBP","in_stock":false},{"title":"7. PTS MASADA - CA SCAR-L","offer_id":55504540631416,"sku":"82360559","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"8. VFC SCAR-H","offer_id":55504540664184,"sku":"41361697","price":24.95,"currency_code":"GBP","in_stock":false},{"title":"9. EF\/S\u0026T TAR-21 COMP","offer_id":55504540696952,"sku":"61273681","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"10. EF ARX160 ELITE","offer_id":55504540729720,"sku":"35069496","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"11. CA KAC LMG - VFC MP5 A\/SD","offer_id":55504540762488,"sku":"29364995","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"12. LCT AK-47\/74\/M - LCT VSS\/AS VAL","offer_id":55504540795256,"sku":"22749468","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"13. A\u0026K MASADA\/ACR","offer_id":55504540828024,"sku":"38940883","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"14. KA CZ 805 BREN - CG M249 FEATHERWEIGHT - A\u0026K M60","offer_id":55504540860792,"sku":"52153452","price":24.95,"currency_code":"GBP","in_stock":false},{"title":"15. EF\/ARES G36KV\/CV - JG G36","offer_id":55504540893560,"sku":"43882168","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"16. EF\/S\u0026T G36C","offer_id":55504540926328,"sku":"44996356","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"17. CA AUG","offer_id":55504540959096,"sku":"10434542","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"18. G\u0026G MP5 A\/SD","offer_id":55504540991864,"sku":"80010259","price":24.95,"currency_code":"GBP","in_stock":false},{"title":"19. VFC\/ECHO1 XCR","offer_id":55504541024632,"sku":"89496485","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"20. CA G36 - CYMA SR-25","offer_id":55504541057400,"sku":"29690450","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"21. Elite Force\/CYMA MP5K - CA SA58","offer_id":55504541090168,"sku":"47626122","price":24.95,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0562\/8097\/3450\/files\/F2_Nozzle_Close_Angled_1944x_d10bfc91-ff2f-43cc-b795-097e07a8085b.jpg?v=1773836879"},{"product_id":"polarstar-fusion-engine-drop-in-kit-gen3-v2-m4-m16-uk-spec-red-low-flow-poppet-red-nozzle","title":"Polarstar Fusion Engine Drop-in Kit GEN3 — V2 (M4\/M16) — UK Spec (Red Low-Flow Poppet, Red Nozzle)","description":"\u003cdiv style=\"background:#edfaf1;border-left:4px solid #27ae60;padding:12px 16px;border-radius:0 6px 6px 0;margin:0 0 16px;font-size:13px;\"\u003e\n\u003cstrong style=\"color:#1a6b3a;\"\u003ePolarstar Fusion Engine Drop-in Kit GEN3 — V2 (M4\/M16) — UK Spec (Red Low-Flow Poppet, Red Nozzle) — \u003c\/strong\u003e Polarstar Fusion Engine Drop-in Kit GEN3 for V2 (M4\/M16) gearboxes — pre-configured with the Red Low-Flow Poppet and Red Nozzle for UK site limits. The original HPA system that started the category in 2011, still the benchmark for adjustability.\u003c\/div\u003e\n\u003cp\u003eThe Fusion Engine launched in 2011 as the first new HPA system in over two decades and won Popular Airsoft's Best HPA Engine award the very first year the category existed. Most other engines on the market trace their lineage back to ideas the Fusion pioneered: dual-solenoid control, full CNC aluminium chassis replacing the entire gearbox, FCU-controlled fire modes, and adjustable poppet\/nozzle restrictors for velocity tuning.\u003c\/p\u003e\n\u003cp\u003eThis V2 GEN3 kit is configured specifically for UK site limits. The Red Low-Flow Poppet restricts the firing air volume to bring velocity down into legal territory while keeping the engine's response time and ROF intact. The Red Nozzle is matched to the poppet for consistent behaviour at lower pressures. If you ever take the rifle abroad to a higher-energy site, swapping to a less-restrictive poppet\/nozzle combination raises the velocity ceiling without any other build changes — the Fusion has 6 colour-coded nozzle options that shift the adjustment range in large increments.\u003c\/p\u003e\n\u003cp\u003eWhere the Fusion still wins against newer engines is the breadth of adjustment in a single build. Maximum cyclic ROF is 30+ RPS in standard configurations. Adjustable velocity, independently adjustable poppet (firing air) and nozzle (feeding), and a full closed-bolt firing cycle for maximum accuracy. The closed-bolt design also makes it less sensitive to hop-up configuration than open-bolt engines, so existing AEG hop chambers and inner barrels typically just work.\u003c\/p\u003e\n\u003cp\u003eThe kit ships as a complete drop-in: lightweight CNC aluminium chassis, FCU, switchboard, wire harness, and all the platform-specific components needed for V2 M4\/M16 installation. It's a full replacement for your AEG gearbox — gears, piston, motor, the lot — so no leaking cylinders, no stripped gears, no broken pistons. A 7.4V to 9.6V LiPo or NiMH battery is needed for the FCU (not included).\u003c\/p\u003e\n\u003ch2 style=\"font-size:16px;color:#1B3A6B;margin:18px 0 8px;\"\u003eSpecifications\u003c\/h2\u003e\n\u003ctable style=\"width:100%;border-collapse:collapse;font-size:13px;margin:0 0 18px;\"\u003e\n\u003ctr style=\"background:#1B3A6B;color:#fff;\"\u003e\n\u003cth style=\"padding:7px 12px;text-align:left;\"\u003eSpecification\u003c\/th\u003e\n\u003cth style=\"padding:7px 12px;text-align:left;\"\u003eDetail\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eEngine\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003ePolarstar Fusion Engine GEN3\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eConfiguration\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eUK spec — Red Low-Flow Poppet + Red Nozzle pre-installed\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003ePlatform\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eV2 gearbox AEG (M4 \/ AR-15 style)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eChassis\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eFull CNC-machined aluminium — complete gearbox replacement\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eFiring cycle\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eClosed-bolt (highest accuracy)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eVelocity (test data)\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003e550 FPS @ 0.20g @ 120 PSI with Black Poppet \/ Blue Nozzle \/ 6.05 × 375mm barrel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eVelocity range\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eWidest of any Polarstar engine — 6 nozzle colours for large adjustments\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eRate of fire\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003e30+ RPS achievable in most configurations\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eAir efficiency\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003e~400+ shots from 13ci\/3000 PSI tank @ 1.5J on 0.28g\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eHop-up compatibility\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eWorks with standard AEG hop chambers and inner barrels\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eMag compatibility\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eTokyo Marui-compatible M4\/M16 AEG magazines (mid-caps, hi-caps, low-caps)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eIn the kit\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eEngine, FCU, switchboard, wire harness, V2 install components\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003ePower\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003e7.4–9.6V LiPo or NiMH for FCU (not included), HPA tank + regulator separate\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003cdiv style=\"background:#1B3A6B;color:#fff;padding:12px 16px;border-radius:6px;margin:18px 0 0;font-size:13px;\"\u003e\n\u003cstrong style=\"color:#fff;\"\u003e💡 Titan Forge Airsoft tip:\u003c\/strong\u003e The Fusion is still favoured by long-time HPA technicians for its breadth of adjustment and field-proven reliability — if you've owned an HPA rifle before and want maximum tuning headroom, this is the engine to choose. New to HPA? The \u003ca href=\"\/products\/polarstar-f2-hpa-engine-bundle\" style=\"color:#cdd6f4;\"\u003eF2 Bundle\u003c\/a\u003e is smaller, lighter, and more air-efficient. Browse \u003ca href=\"\/collections\/hpa-engines\" style=\"color:#cdd6f4;\"\u003eour full engine range\u003c\/a\u003e for comparison.\u003c\/div\u003e","brand":"Polarstar","offers":[{"title":"Default Title","offer_id":55566073201016,"sku":"3264397133","price":499.95,"currency_code":"GBP","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0562\/8097\/3450\/files\/PolarstarFusionEngineDrop-inKitGEN3-TitanForgeAirsoft-1.webp?v=1779266933"},{"product_id":"polarstar-modular-regulator-system-mrs-regulator-only","title":"Polarstar Modular Regulator System (MRS) — Regulator Only","description":"\u003cdiv style=\"background:#edfaf1;border-left:4px solid #27ae60;padding:12px 16px;border-radius:0 6px 6px 0;margin:0 0 16px;font-size:13px;\"\u003e\n\u003cstrong style=\"color:#1a6b3a;\"\u003ePolarstar Modular Regulator System (MRS) — Regulator Only — \u003c\/strong\u003e Polarstar Modular Regulator System — an ultra-compact 3-inch HPA regulator that threads directly onto your tank, eliminating the need for a separate Universal Fill Adapter. Integral on\/off valve, tournament lock, and 40–145 PSI adjustability.\u003c\/div\u003e\n\u003cp\u003eStandard HPA setups need a UFA (Universal Fill Adapter) between the tank and the regulator, which adds bulk and another fitting point where leaks can develop. The Polarstar MRS replaces that arrangement: the regulator body has its own integral tank threads, screws directly onto a 13ci or larger HPA tank, and stands just 3 inches tall in total. The result is the smallest regulator profile available for SLP, LP, and standard paintball-spec HPA tanks.\u003c\/p\u003e\n\u003cp\u003eThe on\/off valve is the standout feature for technicians and field marshals. Most regulators leave the line and downstream components pressurised when removed from the tank — potentially wearing the tank o-ring and threads on every uninstall. The MRS lets you depressurise the high-pressure side of the regulator before unscrewing it, protecting both the tank o-ring and your regulator's internal seals. For players who swap tanks between games or carry spares, this is a meaningful longevity improvement.\u003c\/p\u003e\n\u003cp\u003eThe oversized 4mm piston bore is what sets the MRS apart functionally. High-flow, high-refresh performance even at low output pressures (down to 40 PSI) means you can drive high-ROF engines — F2, Fusion, BLINC-controlled INFERNO — without pressure drop during sustained bursts. Output pressure is adjustable from 40 to 145 PSI as standard; an optional High Pressure spring extends the range to ~200 PSI for setups that need higher input.\u003c\/p\u003e\n\u003cp\u003eAn integral tournament lock secures the pressure adjustment screw with a standard zip tie, which is how UK skirmish event safety officers verify regulator output between games. Compatible with all common HPA tanks (standard and SLP) including HK Army, Ninja, Tippmann and similar. The regulator is sold standalone — you'll need an air line and a QD or filter fitting separately if you don't already have them.\u003c\/p\u003e\n\u003ch2 style=\"font-size:16px;color:#1B3A6B;margin:18px 0 8px;\"\u003eSpecifications\u003c\/h2\u003e\n\u003ctable style=\"width:100%;border-collapse:collapse;font-size:13px;margin:0 0 18px;\"\u003e\n\u003ctr style=\"background:#1B3A6B;color:#fff;\"\u003e\n\u003cth style=\"padding:7px 12px;text-align:left;\"\u003eSpecification\u003c\/th\u003e\n\u003cth style=\"padding:7px 12px;text-align:left;\"\u003eDetail\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eHeight\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003e3 inches (76mm) — sits directly on tank\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eOutput pressure\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003e40–145 PSI adjustable (standard configuration)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eOutput pressure (HP)\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003e~200 PSI maximum with optional High Pressure spring\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eInput pressure\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eUp to 900 PSI — safe with all paintball-spec HPA tanks\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003ePiston bore\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eOversized 4mm — high flow \/ fast refresh\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eIntegral on\/off\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eYes — depressurise before tank removal\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eTournament lock\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eIntegral — secured with standard zip-tie\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eTank compatibility\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eSLP, LP, and standard HPA paintball tanks\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eTank threads\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eStandard HPA paintball thread (no UFA required)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eMaintenance\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003ePiston\/bore clean every 100,000–150,000 cycles\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003eAdjustment tool\u003c\/td\u003e\n\u003ctd style=\"padding:7px 12px;border:1px solid #eee;\"\u003e3\/32 allen wrench for pressure screw, 5\/32 hex for service\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003cdiv style=\"background:#1B3A6B;color:#fff;padding:12px 16px;border-radius:6px;margin:18px 0 0;font-size:13px;\"\u003e\n\u003cstrong style=\"color:#fff;\"\u003e💡 Titan Forge Airsoft tip:\u003c\/strong\u003e The MRS shines on compact in-stock builds where a low-profile regulator matters more than anything else — pair with a \u003ca href=\"\/collections\/hpa-tanks\" style=\"color:#cdd6f4;\"\u003e13ci tank\u003c\/a\u003e for a stock-internal rig, or with a larger tank for a tank-on-back setup. Need a complete rig? Our \u003ca href=\"\/collections\/hpa-accessories\" style=\"color:#cdd6f4;\"\u003eHPA accessories\u003c\/a\u003e includes matching lines and QD fittings.\u003c\/div\u003e","brand":"Polarstar","offers":[{"title":"Default Title","offer_id":55566074642808,"sku":"2450841011","price":139.95,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0562\/8097\/3450\/files\/PolarstarModularRegulatorSystem-MRS-TitanForgeAirsoft-1.webp?v=1779267110"}],"url":"https:\/\/www.titanforgeairsoft.com\/collections\/polarstar.oembed","provider":"Titan Forge Airsoft","version":"1.0","type":"link"}