Griffin Technology NA23103 PowerBlock Reserve for iPhone and iPod, 5 Watt, Black 2 chargers in 1: PowerBlock AC charger plus detachable Reserve battery pack for iPhone and iPod 5 watts of fast charging power from almost any wall outlet Reserve battery extends phone time up to 2 hours, music time by 12, video time by 3, and surf time up to 3 additional hours Energy Star rated to save energy when not in use, without sacrificing performance