Fenix ARB-L21-4000P Rechargeable 21700 BatteryThe ARB L21 4000P battery supports large current output making it ideal for powering lights and other items that are operated at higher power loads. The maximum current for the ARB L21 4000P is 18A, with a continuous output current of 10A. The higher current allows the 21700 battery longer runtimes at higher levels in flashlights. As with all Fenix rechargeable batteries, the 21700 4000 mAH has three sets of overheat protection, including pressure