Dudes sent me a Mophie Juice Pack Air rechargeable battery pack case for the iPhone for testing, and I’ve got to say it’s a cool bit of kit. Installing the thing is a cinch, just plonk the iPhone into the bottom slice, and clip on the top bit and your done, 10 seconds (well 20 if you’re fiddling around trying to get the handset latched into the socket).

Once on, the first thing you notice is the fact that your iPhone has grown, but surprisingly, not as much as you’d expect. I see why they call it the world’s thinnest iPhone battery case. The Mophie people have done a remarkable job of cramming a 1200mAh battery into a shape which doesn’t really make your svelte handset a clunker. Yes it’s bigger, and it will take a bit of getting used to, but the benefit of the improved battery life more than outweighs the chunkier form factor. Especially if you’re an  iPhone power user. And hey, it’s a protective case too. Bargain.

The device is also very clever functionally. There’s a pass through USB charge port, so you can charge and sync the phone in situ, and the on/off switch is a master stroke, as it means you can regulate when you use the extra power, instead of just having the iPhone suck juice from it permanently.

The blue LED status indicators are also a nice touch, to let you know how much charge you have left. All in all it’s a well thought out product and if you’re one of those who rely on your iPhone to keep your business running on the move, then this is probably a must have product. The fact that it extends your iPhone’s work time x 2 really takes the pressure off conserving battery life (you know the feeling, a hurried browse over WiFi rather than a relaxed languid session using 3G). At $79.95 it’s probably one of the best investments you’ll make for your phone, and it’s compatible with the new iPhone model too. Click on thumbnails for larger image.

 The brand new mophie ‘juice pack air’ is designed to virtually double the time you have to Rock, Talk, Surf and Send with your iPhone 3G or 3G S. The juice pack air is a rechargeable external battery concealed inside of a protective form-fitting case for the iPhone 3G & iPhone 3G S. 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.