Fenix ARB-L21-6000 Rechargeable 21700 Li-ion Battery - 6000 mAhThe Fenix ARB L21 6000 21700 rechargeable Li ion battery has a capacity of 6000mAh, providing the necessary voltage and power for long lasting use and increased lumen capabilities. With the same features as other high quality Fenix batteries, such as internal protective circuits and up to 500 charging cycles, the ARB L21 6000 can ensure extended runtime and consistent performance. It also offers three sets of overheat protection pressure relief,