Greenlee Non-Contact Voltage Detectors Use to detect voltage in outlets, lighting fixtures, circuit breakers, wires, and cables or to find a break in a wire. Patented automatic self-test verifies the integrity of the unit. Bright LEDs flash and audible alarm sounds if voltage is present. Silent-mode feature for use in quiet settings. Automatically turns off after five minutes of non-use to conserve battery life Pack of 1