This iPhone 4 External Battery Pack/Back Case is a high quality advanced accessories external battery pack.
Ideal as a back up battery while on the road or holidays.
If you are using your iPhone 4 for an extended amount of time the battery will eventually power down.
This is where the AA battery pack comes into play, simply plug your iPhone 4 into the case and enjoy even more hours of usage.
The battery pack also works as a hard plastic case.
Portable power anytime anywhere.