Fenix Li-ion 21700 3.6 V Mah Rech . 6V 5000 mAh - 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 Specifications for Fenix ARB-L21-5000 Rechargeable Li-ion 3.6V 5000 MAh: Manufacturer: Fenix Battery Quantity: 1 Battery Capacity: 5000 mAh Power: 3.6 volts Battery Type: Lithium-ion Rechargeable Battery Chemistry: Lithium-Ion