... case for iphone 4 1.Capacity: 1900mAh 2.Device Protector 3.battery extender case for iphone 4 Introductions:external Backup Battery Case for iPhone4 ,Micro-USB for charging ... all,pls turn on the switch,When lithium battery is full of power,pls insert iphone4,then turn on the switch ... USB port.Now it is able to charge for lithium batter,after it is full of power,pls operate as above mention ...