It's a case, also a power source, check out PowerSkin.
With twice the power for your smartphone, your life charges on. You can keep working. Keep playing. Keep moving. PowerSkin® is your go-to, go-anywhere, go on-and-on power source. Because battery life is life.
And when (not if) you drop your phone along the way, life charges on. With a sleek, protective design that fits your phone and your style like a second skin, PowerSkin® is there where the silicone rubber hits the road of your life. More, PowerSkin® is XPAL Powered, meaning it's charged by patented battery technology that reflects the highest standards of safety, quality, and performance. We've got you — and your phone — covered.http://www.power-skin.com