I have been using this a couple of days now and I'm very pleased with it, charges itself fast and lasts for a long time. My phone charges quickly and I love the convenience that I can charge my phone on the go. It is really quick and simple to remove the white case that came with the charger. I am very pleased with this and would recommended to anyone.

Maxboost Hybrid iPhone 4S Battery Case / iPhone 4 Battery Case (1900mAH, Fits all versions of Apple iPhone 4 & 4S) - Detachable Battery Charger Case External Rechargeable Battery Pack Charging PoweCase