There’s a lot of backup batteries on the market, but Just|Mobile has one of the few that are Apple-certified for iPhone/iPod. The Gum Plus is compact (3.1 x 2.3 x 0.9 in) and has a rounded aluminum case. Outside are LED lights that act as a battery meter. Inside is a 4400 mAh battery (1A current) that can charge an iPhone to 90% in one hour, and it can recharge the iPhone up to four times before it needs a charge itself. The Gum Plus comes with a mini USB cable for charging and an Apple docking cable to charge your Apple device. It can charge other USB devices; simply supply your own cable. The Gum Plus is $69.95 from the Just|Mobile website.