This is a 1.5 volt alkaline button cell battery commonly used in laser pointers watches children books calculators and medical devices. A button cell battery is a small round battery that is 11.6 mm [0.457 inch] in diameter and 5.4mm [0.21 inch] thick. An alkaline battery is a battery that uses manganese dioxide and zinc to create a reaction and it is an economical alternative to silver oxide batteries while still providing high capacity and long usage. This is a primary cell battery and it is non-rechargeable. This alkaline button cell battery provides long power life and excellent continuous power sources to your device. Works effectively in both low and high temperature.