The TYLT ENERGI 2K [$40] Travel Charger replaces your standard wall charger and keeps your phone charged while on the go. Just plug the ENERGI 2K into your wall and it works like a regular USB wall charger. You can charge any device that charges via USB. The Intelligent Charging Technology prioritizes the charge to the device until it’s fully charged. then it charges the 2200mAh onboard battery. When you need to roll, just unplug the 2K from the wall, fold the collapsible plug down and take it with you; to school, to work, on a train, on a plane, to a game, anywhere, even your hammock.