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. Rechargeable lithium-ion battery 4900 mAh capacity Rated voltage: 3.7 V Nominal capacity at +22°C (72°F): 4900 mAh Designed to power Axion / Digex models Pulsar Battery Pack APS 5 (for Axion XQ & Axion LRF) PL79181