AWLS rechargeable USB batteries are designed for high drain devices. These are available in 18350 and 18650 sizes. The 18350 fits the AWLS Compact Size body along with any other light on the market that accepts 18350 batteries. The 18650 fits the AWLS Full Size body along with any other light on the market that accepts 18650 batteries. The internal design provides short circuit protection, over temperature protection and overload protection. These batteries have built in USB charging capabilities along with standard chargers.