The 1AC II VoltAlert™ AC voltage tester, designed to both beep and light up in the presence of voltage, is a pocket sized voltage detector intended for non-contact, live-not-live voltage detection on electrical circuits found in residential, commercial and industrial buildings. Just touch the insulated tip to a terminal strip, outlet or cord and when the tip glows red and the unit beeps, there is voltage present. Electricians, maintenance, service, safety personnel, and homeowners can quickly test for energized circuits and defective grounds on the factory floor, in the shop, or at home.