The Nitecore 183 is a high-powered Lithium-Ion battery that is used for high-drain devices such as many LED . The 183 has a capacity of 2300 mAh and is protected from overcharging and discharging.

2. NITECORE 189 – battery review (capacity: 3400mAh). Nitecore is a big brand 18650 rechargeable flashlight

rechargeable flashlight 18650 | eBay