Kensington Mini Battery Extender and Charger for iPod and iPhone 1G

If your iPod or iPhone (both first and second generation) is low on battery life, you can simply pop on this battery extender from Kensington to extend its battery life by about double. It attaches to the iPod and iPhone via the dock connector. It also comes with a retractable USB charging cable so you can charge both the extender and the iPod/iPhone at the same time. It is currently available for $40.