Nitecore NL1665R 650mAh USB Rechargeable CR123A 16340 Battery. The NITECORE NL1665R is a 650mAh 16340 micro-USB rechargeable battery that's compatible with multiple 16340 flashlights, headlamps and other electronic powered devices. No charger is needed to recharge this battery, it's equipped with a built-in micro-USB port that allows users to charge the battery directly using any compatible USB power source. Yet, the battery does have the ability to recharge using a traditional charger providing multiple recharge options for users. The NL1665R is equivalent to 500 pairs of CR123 batteries and has a life span of over 500 recharge cycles, helping to reduce the cost of energy to users over time. The battery boasts multiple external safety mechanisms like a microporous barrier to defend internal components and a pressure relief valve to protect against rapid temperature increases and explosions. A built-in high-performance protection circuit protects the battery from overcharging, over discharging and short-circuiting to prevent damage and prolong battery life.