Gomadic Portable AA Battery Pack designed for the Microsoft Zune (2nd and Latest Generation) - Powered by 4 X AA Batteries to provide Emergency charge. Built using TipExchange Technology Integrated circuitry regulates output voltage specific to the Microsoft Zune (2nd and Latest Generation). Advanced logic maximizes overall charger efficiency. Specification: Input Voltage (4 X AA Batteries), Cable length (6 inches), Dimensions (5.0 X 1.5 X 0.75 inches), Circuit Design (Microsoft Zune (2nd and Latest Generation) specific), TipExchange enabled (Yes) Built using the unique Gomadic TipExchange Technology that protects your investment by providing the ability to upgrade charging ports by simply swapping physical connectors. This Gomadic Battery Pack can be reused forever by simply inserting fresh batteries, providing instant power on demand. The rugged composite design is built to last. This product is backed by our comprehensive Gomadic Lifetime Warranty.