The PowerSkin for iPhone 4 ($80) is a silicone case with a built-in rechargeable 2,000 mAh battery that claims to double your device’s battery life with patented “XPAL Power” battery technology. Like most battery cases, it uses a mini-USB port to charge and sync your iPhone simultaneously, and you can turn the case on and off when necessary. The four-LED battery indicator will let you know how much juice you have remaining at the touch of a button.
PowerSkin for iPhone 4: The Electric Surfer [Review, Battery Case Week]
![PowerSkin for iPhone 4: The Electric Surfer [Review, Battery Case Week] PowerSkin-case-for-iPhone-4-1](https://cdn.cultofmac.com/wp-content/uploads/2011/08/Screen-Shot-2011-08-26-at-17.12.06-e1314375219198.png)