Unique Gomadic Portable Rechargeable Battery Pack designed for the Peek GetPeek Pronto - High Capacity Gomadic charger that fits in your pocket Specification: Internal Battery (7800mAh lithium polymer), Input port (microUSB), Output Port (Standard USB), Onboard Circuit Design (Peek GetPeek Pronto Specific), Dimensions (2.75 X 3.25 X 0.75 inches), TipExchange enabled (Yes) Very easy to operate. Simply connect Peek GetPeek Pronto, 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 Peek GetPeek Pronto (accurate to 0.1v). Continue to use your Peek GetPeek Pronto for hours OR recharge it on the go without being tethered to a wall outlet Internal circuit protects the Peek GetPeek Pronto from various power ailments including surges, overcharging and short circuiting. Advanced logic maximizes charger efficiency