Give your Apple iPhone 4 or 4S protection and power with the Apple iPhone 4 / 4S Power Pack External Battery Case w/ USB Port. The hard shell case will prevent dust, dirt and scratches from accumulating on your phone, keeping it looking good as new. The built-in battery provides additional power to your iPhone 4 or 4S. An LED light lets you know when your battery case is on. A simple touch of the button allows you to control when your case provides power to your phone. What truly makes this case unique is the additional USB output, so you can charge a second device straight from this case!