The Fenix ARB-L21-5000U is a high-performance, li-ion battery designed to power high drain devices that support 21700-size batteries like your favorite flashlights, lanterns, and more. We love to pair it with Fenix PD36R, TK22 V2.0, or TK22UE.
Simply charge the Fenix 21700 battery using the built-in USB-C charging port or using another compatible battery charger. With built-in overcharging and over-discharge protection, the ARB-L21-5000U is designed to last over 500 charge cycles. The cathode, (positive button top) features a battery charging indicator: red for charging, blue for fully charged. A 12 month free warranty period means you will never have to worry about this battery leaving you in the dark.