Gomadic High Capacity Rechargeable External Battery Pack suitable for the iRulu Android Tablets Specification: Internal Battery (7800mAh lithium polymer), Input port (microUSB), Output Port (Standard USB), Onboard Circuit Design (iRulu Android Tablets 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 iRulu Android Tablets (accurate to 0.1v). Very easy to operate. Simply connect iRulu Android Tablets, press activation button on pack, and charging begins. Quick start guide included. Elegant, compact design is approximately the size of a standard deck of playing cards. Rugged exterior is built to last and backed by Gomadic Lifetime Warranty Built using unique Gomadic TipExchange Technology that protects your investment by providing the ability to upgrade charging ports by simply swapping the physical connector.