Feature:

Compactly and exquisitely design, being the thinnest and lightest type.
Smart Li-ion polymer battery
5-LED light indicators
Built-in FM transmitter
4 transmit frequencies: 88.1, 88.5, 88.9, 89.3 MHz
Non-slip, comfortable grip, and prevent your iPhone 4 4s from scratches and dust

Specifications:

Input: 5V 500mA
Output: 5V 500mA
Capacity: 1600mAh (Li-poly)
Standby time: up to 360 hours
Talk time: up to 6 hours on 3G
Internet use: up to 6 hours on 3G, up to 10.6 hours on WI-FI
Audio play: up to 36 hours
Video play: up to 10 hours
Charging time: up to 3.5 hours
Color: black
Package size: 9 x 2.7 x 20.5 cm
Package weight: 124g