If you want to double your iPhone 4′s battery life, the Exolife battery case claims to do just that. But even if it doesn’t, at least you get a case that’s slim, light, and will give you some extra juice. It’s good looking.
The case weighs just 59 grams including the rechargeable Lithium polymer battery. It even features a polycarbonate frame and an Illuminated power meter. It costs about $90 and will be available at the end of the month.