Popcase, the ultimate modular iPhone battery case

POP case is the first iPhone battery case with a modular design. With a super slim protective case and a removable battery pack that attaches perfectly on the back of the case so it won’t hand or swing loosely. POP case is the best solution for both protection and power. Elegant 2 in 1 design transforms your POP case to what you need. It comes with a detachable battery pack that you can easily snap on the back of the case when you need an extra charge but can be removed if you wanted to travel more lightweight.
http://www.thepopcase.com/