I'm so over being on the go and having my iPhone lose its charge — normally the battery life is long enough to last through a day of normal use, but from time to time I find myself in need of a charge. The Mophie Juice Pack Air ($80) is the thinnest rechargeable iPhone case on the market, and is available in four colors. It's a hard, protective case that houses a rechargeable battery to give your iPhone a boost any time the battery gets low. When your phone is in the case, it will automatically use the external battery before its own. Plus, the case also has an LED indicator light to let you know exactly how much power is left.