Unique Gomadic Portable Rechargeable Battery Pack designed for the Sonim XP Strike - 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 (Sonim XP Strike Specific), Dimensions (2.75 X 3.25 X 0.75 inches), TipExchange enabled (Yes) Integrated circuitry tailors output voltage and charging current to exact specification of the Sonim XP Strike (accurate to 0.1v). Very easy to operate. Simply connect Sonim XP Strike, press activation button on pack, and charging begins. Quick start guide included. Continue to use your Sonim XP Strike for hours OR recharge it on the go without being tethered to a wall outlet Designed with a front facing LED display that clearly display the current battery capacity at the touch of a button