Third Rail Mobility has made an iPhone case that allows you to not only keep extra power around, but actually swap batteries when and as needed. The ability to change batteries is a feature Apple has never provided for the iPhone but something traditional smartphone users from other platforms have often depended on to have enough power with them on the go. While there are tons of places to recharge now, and a variety of battery cases, dongles and more, if you're going to be away from power for a long period of time, swappable battery can still be the best solution. Thanks to Third Rail Mobility, it's available for those who really want it for the iPhone now as well.

Check out the video above, shot live at CES 2012, to see it in action.