Rechargeable Li-Ion batteries Battery Pack APS2 / APS3 are designed to be used with digital and thermal riflescopes Pulsar (Thermion Digex etc.) monoculars Axion (APS3) binoculars Merger (APS3) and to significantly increase their self contained operating time. Power your favorite thermal and digital night vision devices with the APS3 Battery Pack. With a 3.6 charge voltage the APS 3 Battery provides a 4 hour battery life in select Axions and a 6-8hour battery life when paired with the internal battery in Thermion riflescopes. The APS 3 can be charged through the mini-USB port on Axion monoculars and with the supplied APS battery charger that comes stock with all Thermion riflescopes. Only use the charger supplied with the Battery Pack (may not be included).