LiPo

A lithium-polymer cell stores significantly more energy per gram than nickel-metal-hydride and discharges that energy faster on demand. In practical airsoft terms: same physical battery size, more shots per charge, faster motor spin-up between trigger pulls. For a rifle running a high-speed motor, a tuned gearbox, or simply an MOSFET-equipped trigger system, LiPo is the chemistry the rifle was designed around. Try to run that rifle on NiMH and it'll feel sluggish even when nothing's mechanically wrong.

Two voltage standards dominate UK airsoft. 7.4V (2S, two cells in series) is the entry-level LiPo — drop-in replacement for the old 8.4V NiMH stick batteries that came with most older AEGs, no rewiring needed, marginally better performance than the NiMH it replaces. 11.1V (3S, three cells in series) is the upgrade path — significantly more power, noticeably faster trigger response and rate of fire, but requires the rifle to be MOSFET-equipped or AEG-rated for 11.1V to avoid arcing damage at the trigger contacts. Check your rifle's manual before going 11.1V.

Physical form matters as much as voltage. Stick batteries fit AK-pattern stocks and tube-style M4 stocks. Nunchuck (split-pack) batteries fit M4-pattern crane stocks where the cells need to wrap around the buffer tube. Buffer tube cells fit modern M4 stocks with internal battery space. Mini-shape cells fit SMG-pattern rifles where space is tight. Browse the collection by your rifle's battery compartment shape — listings show dimensions. Pair with the right LiPo charger — never charge LiPo on a NiMH charger, even briefly.