Fluke 1ACA1II VoltAlert Electrical Tester, 90-1000V AC is easy to use - just touch the tip to a terminal strip, outlet, or cord. When the tip glows red and the unit beeps, you know there is voltage in the line. 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.