mophie Juice Pack air [$79.95 - iMore Store link] is he worlds thinnest rechargeable battery case for iPhone 3G & iPhone 3GS.
The juice pack air is a rechargeable external battery concealed inside of a protective form-fitting case for the iPhone 3G & iPhone 3GS. It offers you the full protection of a hard-shell case while providing virtually twice the battery life of the iPhone alone; all in an ultra-thin, light-weight, low-profile design.
This is the first Apple certified Works With iPhone 3G(S) attached battery in the world! The juice pack air is specially designed for iPhone 3G & 3GS and has passed the strict over-the-air performance tests by an Apple designated test lab. As a result, the mophie juice pack air has been officially certified by Apple Inc. as a Works with iPhone 3G(S) product!
The mophie juice pack air for iPhone 3G & 3GS, also uses Apple designated connector, which can only be ordered through Apples certified vendors. This ensures its 100% compatible with your iPhone 3G or 3GS.
Extended battery and the full protection of a ultra-thin, light-weight hard case.Choose the color that matches your iPhone 3G & 3G S or your style. Black, white or purple.The built-in on/off switch allows you to use the juice pack air just as a case or as a battery at the flick of a switch. The juice pack air is fullycompatible with iPhone 3G and iPhone 3G S.Charge and sync your iPhone to iTunes without removing it.
It extends the time that you can use your iPhone 3G or 3GS in these ways (additional hours):
For more on the mophie Juice Pack air, check out TiPb's iPhone Accessory Store...