Gomadic Portable AA Battery Pack designed for the T-Mobile G2 - Powered by 4 X AA Batteries to provide Emergency charge. Built using TipExchange Technology Integrated circuitry regulates output voltage specific to the T-Mobile G2. Advanced logic maximizes overall charger efficiency. Built using the unique Gomadic TipExchange Technology that protects your investment by providing the ability to upgrade charging ports by simply swapping physical connectors. Specification: Input Voltage (4 X AA Batteries), Cable length (6 inches), Dimensions (5.0 X 1.5 X 0.75 inches), Circuit Design (T-Mobile G2 specific), TipExchange enabled (Yes) Internal circuit designed to protect your T-Mobile G2 from power surges, overcharging and short circuiting. A must have accessory for the frequent traveler, camper or heavy T-Mobile G2 user.