Gomadic High Capacity Rechargeable External Battery Pack suitable for the Olympus VR-320 Specification: Internal Battery (7800mAh lithium polymer), Input port (microUSB), Output Port (Standard USB), Onboard Circuit Design (Olympus VR-320 Specific), Dimensions (2.75 X 3.25 X 0.75 inches), TipExchange enabled (Yes) Very easy to operate. Simply connect Olympus VR-320, press activation button on pack, and charging begins. Quick start guide included. Integrated circuitry tailors output voltage and charging current to exact specification of the Olympus VR-320 (accurate to 0.1v). Internal circuit protects the Olympus VR-320 from various power ailments including surges, overcharging and short circuiting. Advanced logic maximizes charger efficiency Continue to use your Olympus VR-320 for hours OR recharge it on the go without being tethered to a wall outlet