External Backup Battery/Charger for USB-Charging Devices The Extech PWR5 offers a compact Power Bank that acts as an external backup battery/charger for your portable USB-charging devices and provides you backup power at the time when you need it most...away from a power source! The PWR5 Power Bank supplies 2800mAh of power. It also has a convenient built-in LED flashlight. Compatile with smart phones, tablets MP3/4 players, digital cameras, GPS and other USB portable devices. Complete with micro USB cable.