Mercury USB-B108 Emergency Battery Powered USB Charger - 421.770UK

This compact, portable USB power bank allows devices to be charged from 4 AA batteries while on the move. Ideal for smartphones, tablet computers and many other devices.
Powered by 4 AA batteries
Features a battery level indicator (green for alkaline and blue for rechargeable)
Power supply 4 x AA batteries (not supplied)
Output current 800mA
Output voltage 5Vdc
Dimensions 79 x 34 x 34mm
Weight 40g