Black + Decker's new Smartech Bluetooth-enabled batteries sync up with the company's mobile app so you can monitor your power tool's battery life. Obviously. You can also use their tracking system to hunt down power tools buried in your garage. Amazing. But really, the best thing about these batteries is that they not only bring your chainsaw roaring to life, but can also power your external phone or tablet through their built-in USB ports. Cool! The batteries work with any of the company's 20V Max tools and will retail for $69. Time to fire up that Bluetooth-connected lawn trimmer!