The Juice Pack Air by Mophie is a rechargeable external battery concealed within a protective case for the iPhone 3G and 3GS. Its the worlds thinnest rechargeable battery case and can virtually double your battery life. The Juice Pack Airs hard shell case also offers protection for all corners of the phone in a light-weight, low profile design. Buy from Amazon: www.amazon.com

Mophie juice pack air for iPhone 4 Get on-the-go power for the iPhone 4 in a light-weight and ultra-thin external rechargeable battery case. The mophie juice pack air™ is designed to virtually double the time you have to Rock, Talk, Surf and Send with your iPhone 4! 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. Proud winner of a CES Innovations 2011 Design and Engineering Award. Www.gadgetu.net