With a 3.7 charge voltage, the APS 5 battery pack holds a battery life of up to 4 hours in Axions. The battery pack is designed to fit the Axion Thermal Monocular. Battery Used Type: Li-Ion Quantity: 1 Features Rechargeable lithium-ion battery 4900 mAh capacity Designed to power Axion / Digex models Fits Models: Axion XQ, Axion XQ LRF, Proton FXQ, Proton XQ Battery Type Li-Ion Rated Capacity (MilliAmpere-hour Rating), mAh 4,900 Charging Voltage, V 3.7 Battery charge indication Yes Pin type for battery charger microUSB Body Material Plastic Operating Temperature -4 to 140 / -20 to 60 F / C Length 3.3 / 85 in / mm Width 1.02 / 26 in / mm Height 1.02 / 26 in / mm Weight 2.8 oz