... out of power,it can be just attached perfect Attachable Battery Pack for iPhone and iPodFeatures: 1,Made for iphone4,3G ... 4,Non-slip grip design Product Modle:T4 Color :white Battery:Lithium-polymer battery Capacity:1500MAH(3.7V) USB Output voltage:5V USB ... Output current:500MA Packing:Battery x1,data cableX1 Lithium-polymer battery: more stable and safe than Lithium-ion Cupule design to fit ...