Gomadic Portable AA Battery Pack designed for the Motorola ROKR E8 - Powered by 4 X AA Batteries to provide Emergency charge. Built using TipExchange Technology Specification: Input Voltage (4 X AA Batteries), Cable length (6 inches), Dimensions (5.0 X 1.5 X 0.75 inches), Circuit Design (Motorola ROKR E8 specific), TipExchange enabled (Yes) Integrated circuitry regulates output voltage specific to the Motorola ROKR E8. 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. The rugged composite design is built to last. This product is backed by our comprehensive Gomadic Lifetime Warranty. This Gomadic Battery Pack can be reused forever by simply inserting fresh batteries, providing instant power on demand.