WORKS FOR iPHONE 4 and 4G. Also iPhone 3GS, 3G, 2G, iTOUCH, iPod. If your apple device depletes its battery early in the day then this is a "must have" accessory for you. You plug the handy, light weight (LESS THAN 2 OUNCES), portable STITCHWAY iPHONE BATTERY BOOSTER into the input port of the phone and you get a rapid total recharge. WIRE FREE. The charger attaches directly to the phone. . It will more than double the usage time of the phone. Or you can simply attach the charger and, if not used, will fully recharge your depleted phone in about 2 hours. 1900 mAh, THE LARGEST CAPACITY COMPACT BACKUP POWER FOR iPHONES on the market (almost twice the charging power of a 1000 mAh unit). NOTE: mAh is how batteries are rated for capacity power. The higher the mAh rating, the more powerful the batteries. Charge battery with same power cables that came with your iPhone. WORKS WITH 3G S, 3G, 2G iPHONES; iTOUCH; ALL iPOD NANOS & CLASSIC