Gomadic Portable AA Battery Pack designed for the Garmin Forerunner 305 - 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 (Garmin Forerunner 305 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. Integrated circuitry regulates output voltage specific to the Garmin Forerunner 305. Advanced logic maximizes overall charger efficiency. The rugged composite design is built to last. This product is backed by our comprehensive Gomadic Lifetime Warranty. A must have accessory for the frequent traveler, camper or heavy Garmin Forerunner 305 user.