Meet the bKey: a compact battery charger for smartphones that you can wear on your keychain. The device has a built-in USB tip to charge it. You also get a micro-USB or iPhone tip, depending on the version that you pick up. There is no need for you to carry a cable to charge your phone. The device fits in your pocket and has enough juice to keep your phone running for an additional 30 minutes (230 mAh battery). In fact, the bKey can hold its charge for over 30 days. You can get it on Kickstarter.