7.4v 250mAh Valken Battery (LiPo). A tiny pack made specifically for running the Polarstar, Valken V12, and HPA style fusion engines. Connects straight to your JST connector and will charge on a standard Lipo charger. Includes additional balancer adapter to fit all LiPo chargers (if needed). The ultra small battery will fit in virtually any area of your gun, so rest assured this is a much better choice than a standard airsoft battery. Made by Valken V Energy.