Just Mobile BakPak™ is lightweight backup battery for iPhone. Charge it up using the built-in USB cable and the BakPak™ will have enough power to completely refill your iPhone. Just strap on the rubber bindings and plug in the built-in lightning cable. Available in a range of colors, with adjustable bindings to fit a variety of iPhones, BakPak™ is the most stylish and convenient way to stay charged up – even on your most epic days.