I got this gadget for Christmas and have just now tried it out. It’s the Powerbank from Boombox. You charge it from any USB port and it will recharge your phone later when you are away from AC charging power. It also has a built in flashlight. A red/green/blue LED lets you know if it’s charging itself from a USB port, when it’s fully charged and when it’s charging your phone or other device. I’m not sure where my gift giver got this but as Neil WA4A…Z…….L says “Google is your friend”.
Some other similar chargers are reviewed here:
http://www.huffingtonpost.com/jonathan-handel/chargers-and-power-banks_b_3665760.html