Backup power for iphone Features:1) Built-in USB cable.2) Direct USB Charging from computor or USB charger.3) Automatic tests iphone/ipod function.4) Compatible with all iphone / ipods.5) 4 LED shows charging status.6) 1 button tests power.7) High quality Li-ion Cell.8) Can recharge up to 500 times. Specification:Input:     5V/500 mACapacity: 1000 mAOutput:   5V/500 mA User Manual:Bottom Button: Bottom button shows remaining power.Input:  4 LED turn flash one after another while charging from the charger, 4 LED light when charging completely.Output: 4 LED flash one after another while charging  for iphone, not flash when the power use up. Charging time:  around 2 hours thru travel charger for iphone.  Around 4 hours USB charging cable for iphone.