The popular 18650 battery is a solid choice: its larger than an AA battery but slimmer than a C battery, delivering a 3.6-volt output with an impressive capacity of 3400 mAh in this model. Increasingly used in flashlights, this battery is ideal for long trips, with charging options such as a power bank; it can also be convenient to buy one or more 18650 batteries as spares. As a bonus, this model offers versatile charging options. It features a direct USB-C connector on the side (cable not included) but can also be charged with a compatible 18650 charger or the flashlight's own charging port, if available. Fenix batteries are safe and reliable, with built-in protection against overcharging, deep discharge, short-circuiting, and impacts. Typical of the ARB-L18 series, this battery operates in temperatures from -20°C to +60°C. - Charging indicator (red = charging, blue = ready) - Capacity of 3400 mAh - Do not expose the battery to heat or dispose of it in water. - After extended sto