There's a big 6,000-mAh battery wrapped in the rugged skin of Mophie's Powerstation Pro. It can put out up to 2.1 amps, which means it can charge smartphones as well as more power-hungry gadgets like tablets. It's completely dustproof, too, and can handle direct sprays of water, so rain is no problem. And at just one pound, it won't weigh down your go-bag. [$130; mophie.com]