It's a myth that phone cases must choose between form or function. Boostcase, which is currently available for the iPhone 4 and 4S, combines both seamlessly. It's a modular system with a 1900mAh battery pack that doubles the life of your device. And, while it does add some bulk, it has two distinct advantages over similar options like Mophie's Juice Pack. For one, the battery is removable -- so you only need to make space in your skinny jeans if you know you're going to need it. Additionally, since it's modular, you're able to customize it to your liking. Batteries are available in black or white, while the simple plastic cases are available in a veritable cornucopia of hues. The Boostpack charges through standard micro USB, and can actually charge your iPhone directly -- eliminating the need for that pesky proprietary 30-pin connector. A battery and case package is available for $80, while standalone plastic cases cost #35. We're told the batteries will also be sold individually for between $50 and $60. Check out the hands on gallery below.