Juice pack.

The All-New mophie ‘Juice Pack 3G’ is designed to more than double the time you can rock, talk, surf and send with your iPhone 3G

This is the first Apple certified ”Works With iPhone” attached battery in the world!

The Juice Pack is a rechargeable lithium polymer battery in the form of a non-slip, soft grip case. It extends the time that you can use your iPhone 3G in these ways (additional hours):

* Standby Time – Up to 350 hours
* Talk Time – Up to 6 hours on 3G | Up to 12 hours on 2G
* Internet Use – Up to 6 hours on 3G | Up to 7 hours on Wi-Fi
* Audio Playback – Up to 28 hours
* Video Playback – Up to 8 hours

via mophie