Fenix ARB L21 5000U USB Rechargeable 21700 Li-ion Battery

Fenix ARB-L21-5000 is a high-capacity 21700 Li-ion rechargeable battery built for more power and longer run times. Additional features include a protection circuit in the anode to help prevent short circuits, over charge/discharge and over heating. Pressure relief vents which expel waste gas in the rare case of an internal short circuit preventing an explosion. Battery capacity up to 5000mAh. 500 charging cycles. Currently recommended for the HT18, PD36R, TK22 V2.0, and TK22 UE.  The TK22 V2.0 and TK22UE require a charger to charge the battery.