LLTrader Electric Socket Tester Pen AC Power Outlet LED Light Voltage Detector Sensor 90-1000V Long life and low power consumption; Compact, safety, & easy to carry The next generation VoltAlert AC non-contact voltage testers are easy to use -- just touch the tip to a terminal strip, outlet, or supply cord. When the tip glows red and the unit beeps, you know there is voltage present. Electricians, maintenance, service, safety personnel, and homeowners can quickly test for energized circuits in the workplace or at home. Frequency Range: 50 to 500 Hz; Test Voltage Range: 90-1000V; AC Safety Rating : CAT II 1000v; Powered By: 2 x AAA Batteries (Not included) A perfect tool kit for home and electric industry uses Ideal design for testing power cables, circuit breakers, wall sockets, junction boxes, fuses, etc Just press the button, white LED light can be always on when there is absence of voltage \"Beep\" sound and red flashing LED would indicate the presence of voltage Totally insulated, no exposed metal or conductive parts