Unique Gomadic Portable Rechargeable Battery Pack designed for the Replay XD XD1080 / XD720 - High Capacity Gomadic charger that fits in your pocket Integrated circuitry tailors output voltage and charging current to exact specification of the Replay XD XD1080 / XD720 (accurate to 0.1v). Specification: Internal Battery (7800mAh lithium polymer), Input port (microUSB), Output Port (Standard USB), Onboard Circuit Design (Replay XD XD1080 / XD720 Specific), Dimensions (2.75 X 3.25 X 0.75 inches), TipExchange enabled (Yes) Very easy to operate. Simply connect Replay XD XD1080 / XD720, press activation button on pack, and charging begins. Quick start guide included. Designed with a front facing LED display that clearly display the current battery capacity at the touch of a button Continue to use your Replay XD XD1080 / XD720 for hours OR recharge it on the go without being tethered to a wall outlet