Extend your freedom with the CasePower™ POPPER for iPhone 4 with an inbuilt light-weight, ultra-thin rechargeable battery seamlessly integrated into a protective case. The unique and slim design is so thin most people recognize it as a normal case. Surprise them with an inbuilt battery :) Another cool feature is the 3 optional side panels that are included. Individualize your CasePower," - what color am I today?"