Mophie Juice Pack Air Back up Battery for iPhone 4 (1500mAh) - White

The juice pack air is a rechargeable external battery concealed inside of a protective form-fitting case for the iPhone 4. 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. From the Manufacturer Get the most out of your iPhone 4 with the Mophie Juice Pack Air made for iPhone 4. This durable, ultra-thin case houses a rechargeable battery that virtually doubles your time to rock, talk, surf and send, while protecting your iPhone from everyday wear and tear... and does it all with a style that mirrors the aesthetic of the iPhone. With the Juice Pack Air protecting and charging your iPhone, you can enjoy up to 36 extra hours of audio and nine extra hours of video playback, in addition to iPhone's battery life.

Rechargeable smart battery concealed inside of a low-profile, light-weight, soft-touch, 2-tone metallic case; made for iPhone 4
A protective form-fitting case with an ultra-thin, light-weight, low-profile design
Adds up to 6 hours of talk time (up to 12 on 2G) and 5 hours of Web browsing on 3G (up to 9 on Wi-Fi) to your iPhone