One of the few knocks on the iPhone 4S has been its battery life. While our own iPhone doesn’t seem to be plagued with any battery-sucking gnomes, having a longer battery life, when you need it, is never a bad thing. PowerSkin makes a number of cases for major mobile phones (ahem, your iPhone) that provide back up battery for the device of your choosing. Each case is made of recycled silicone and protects your phone like any other bumper case would.

We got to test out the PowerSkin on our iBeloved and it saved us in a couple of pinches. The PowerSkin offers a second full charge for the iPhone, doubling your use time. Yes, it may be bulky in comparison to other streamlined cases, but considering the extra Li-Ion it packs, the size is easily manageable. We found ourselves throwing it into our bag each day instead of using it as our full-time case, then putting it into service when running somewhere after work with our battery in the red and no time to plug into a charger. Pair the two and in a few minutes you’re good to go. If you’re a heavy traveler, then consider the PowerSkin a must-have.

More photos after the jump.

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