The charger that comes with the Airpad is 5 volts DC, 1000ma of current. Radio Shack sells a charger that that is 1000ma @ 5vdc and a 2.5A @5vdc both units work and come with the special tip to insert into the Airpad tablet. Just pay special attention that the + is on tip side. This is written on the tip that attaches to the wire from the power supply. I keep one at my work site and the original power supply that came with the Airpad at home.