Gomadic Portable AA Battery Pack designed for the Insignia MP3 Player - Powered by 4 X AA Batteries to provide Emergency charge. Built using TipExchange Technology 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 (Insignia MP3 Player specific), TipExchange enabled (Yes) Integrated circuitry regulates output voltage specific to the Insignia MP3 Player. Advanced logic maximizes overall charger efficiency. This Gomadic Battery Pack can be reused forever by simply inserting fresh batteries, providing instant power on demand. A must have accessory for the frequent traveler, camper or heavy Insignia MP3 Player user.