The Klarus Rechargeable Battery 18GT-36UR has a capacity of 3600mAh and can be recharged multiple times for long-lasting power. It features a built-in USB port for easy charging and has protection circuitry to prevent overcharging, over-discharging, and short-circuiting. The battery is compatible with various Klarus flashlights and other devices that accept 18650 batteries. It is a reliable power source for outdoor enthusiasts, professionals, and anyone who needs a dependable rechargeable battery.