There’s nothing worse than being out and about with your smartphone with a battery that’s about to die. Welcome the Eton Boost 8400 (etoncorp.com). This handy battery backup at full power can charge most smartphones three times and can charge two USB devices at the same time, including any tablet. The 8400 milliampere hour battery fits easily into your pocket or purse, and with a simple shake, the LED lights will let you know how much juice is left. When it’s time to recharge, simply plug it into your computer or wall outlet. A great device that is a saving grace during those times when your cell needs a boost. Available for $79.99 at amazon.com.