I love my iPhone but even with the improved battery life of the 3GS it is still a struggle to survive a full day away from power.
There have been external battery pack ‘backpacks’ before but most were fugly and there is no greater crime than to spoil the fine lines of an iPhone. And so it was with much hope that I ordered a Mophie Juice Pack Air.

Designed as a very svelte and slim case for your iPhone, the Juice Pack Air doubles the battery power of your iPhone whilst adding only a little bulk. The case is so well designed that it could easily be mistaken as a standard case.
On the back is a small button and four LEDs to indicate the charge level of the battery pack. On the bottom is the new micro-USB connector that is used to charge the battery and that of the iPhone if connected. It can also be synced via this connector and the requisite micro-USB lead is supplied. A small switch allows to switch the battery pack on/off as desired. When on it will power the iPhone and charge the battery.

It all works beautifully and allows me to use the iPhone as heavily as I wish, watch video and listen to music to my hearts content.

Not cheap at £69.95 but ticks all the boxes, works superbly and the only criticism that I could make is that the fit of some of the parts isn’t perfect, the shut-line of the top half of the case is a little rough in areas but this is me being finnicky. The image on the left shows some of the small gaps that appear in some places. I’m sure better quality control could resolve these?
One other unexpected benefit is the case design redirects the speaker output forward via the two sculpted vents either side of the dock connector. If you play games you’ll find this a great help as many landscape oriented games result in your hands obstructing the speakers.
The Juice Pack Air is available in white, black and purple and is suitable for 3G and 3GS iPhones.