Looking for a mobile power supply, I came after a long search on the 3G JUICE. The battery delivers what it promises. That he actually manages an empty iPhone 3G (below 10%) within 2.5h again fully charge and during operation of the iPhone. After that, however, the 3G JUICE should again to the wall socket for a second time does not manage this feat, unfortunately. Still, I can recommend this battery at any time, since it has already helped me in many critical situations out of a jam. Thanks to its compact design, it is a constant companion.