backup battery with FM Transmitte for iphone4 new and best battery for iphone,OEM service Super thin and light,

It is a FM Transmitter, It is more a Smart Emergency Battery Cover!Super thin and light, it is the most thin and light battery cover for iphone 4 in the world at present!!!1.With Smart monitoring system inside2.With smart power charging management, monitoring circuit and timing function.3.With automatically power off function when the mobile is charged enough.4.With battery capacity indication function in different capacities at 20%,40%,60%,80%,100%5.With 4 FM transmit frequencies: 88.1/88.5/88.9/89.3MHz6.With FM transmit frequency memory function.7.With auto power off function in 60 seconds when there is no audio input. 8.With supporting Iphone 4 data Synchronization function.Specifications:Smart Li-ion Polymer Battery, Four LED light indicators Non-Slip, Comfortable Grip Designed for iPhone4Input:5V-500mAh; Output:5V-1000mAh;Capacity:1600mAh(Li-Poly) Product Compatibility: iPhone4 Standby time : 250 hoursProduct Dimension:123×60×14.5mm Weight:68g Charging cable included

backup battery with FM Transmitte for iphone4