ON THE WAY 4pcs Rechargeable 18650 4000mAh 3.7V Li-ion Black and White Batteries with 1pc Battery Charger and 1pc Touch Pen 1.It has short circuit, over charge and discharge protection so that you can use it without worry. 2.It is a 4000mAh rechargeable battery, most flashlights accept this 18650 battery and shelf life is around 10 years and it is very environmental. 3.This 18650 battery is compatible with various kind of flashlights and LED headlamps, bike lights and etc. 4.It has no memory effect, so it can be recharged at any time. 5. It provides excellent continuous power sources to your device.