The Fenix ARB-L21-5000U is a high capacity 21700 Li-ion rechargeable battery with a protection circuit in the anode to help prevent short circuits, over charge/discharge and over heating. The battery also includes pressure relief vents which expel waste gas in the rare case of an internal short circuit preventing an explosion.
USB Type-C charging interface
Protective circuit inside the anode
500 charging circles
Please Note: This battery is Not an 18650 battery and it is not compatible with 18650 battery powered lights