Finally got around to tackling one of the iPhone's biggest drawbacks - when I have 3G, Location Awareness and WiFi all running in the car to help navigate you can literally watch the battery run down. Anything over a 2 hour car journey has been impossible this way. I'm really impressed with this Powerjolt so far. It's well made, fits very snugly into my 12V socket and the iPhone plug is a lovely solid fit. Even better, Carphone Warehouse had it substantially reduced.