"This universal battery backup is a perfect solution for re-charging your USB device no matter where you might be when one does not have access to a USB charging source. When your USB device gets low on its vital life supply, plug the USB device into the charging ports on this universal external battery backup and get it back up to full capacity.
The charger works with iPods, iPhones and various other USB devices with Mini and Micro USB connections. Equipped with a one touch battery indication for turning the backup battery on or off for your convenience. Self-consumption is low, only 50uA, so it’s able to last while out and about. Charging the battery is simple and can be charged within 5 hours under their max output, by a PC, a USB wall charger or your car charger." text from monoprice website.