You can use the accompanying USB cable to charge your iPhone 4 or 4S. But if you want an innovative way to charge it, the JuiceTank iPhone 4 case with wall charger would be able to catch your eyes.
JuiceTank is an innovative protective case designed for both iPhone 4 and iPhone 4S. As we can see from the images, the iPhone 4S case features form-fit, rugged design, and is constructed of solid polycarbonate, plus a soft touch rubberized lining in order to protect the iPhone 4 or 4S from bumps and scratches. Most importantly, a wall charger has been integrated into the iPhone 4 case, so you can conveniently plug your iPhone 4 into an outlet for charging without any USB cord, while the reserved micro USB port also allows you to charge your iPhone via a USB cable.
At present, the designers of JuiceTank iPhone 4 case are raising fund on Kickstarter. Pledge $55 will let you own the iPhone 4 case with wall charger. If you’re interested, jump to Kickstarter official site for more details. Additionally, if you need other options, you might like to check the iPhone 4 case with USB drive and more via “iPhone 4 case” tag.