The Fenix ARB-L21-5000 Li-ion rechargeable 21700 battery provides the voltage and power needed for extended runtime and higher lumen capacities. The ARB-L21 includes protective circuits inside the anode and up to 500 charging cycles. Also included are the three sets of overheat protection: pressure relief, microporous, and PTC cathodal block. 7.5a Maximum current, charging Current: 1A recommended, 5A Maximum.*Note- Does not include an on-board USB port for direct charging