Get more out of your media player, iPhone or iPod: more music, more video, more talk, more surfing. More than just a battery extender, TuneJuice actually recharges the battery in your rechargeable USB device (including your iPhone or iPod) using 3 standard AA batteries (the first set are included in the package). You will never have to cut short a conversation or a song. Just plug in TuneJuice, and recharge your battery on the spot. TuneJuice is a must-have for air travel, camping, road trips or anywhere you could face the ugly prospect of a dead battery. Use the included dock cable to charge iPod or iPhone, or plug your own USB device's cable into TuneJuice's Type A USB connector.