Klein Tools NCVT-3 Non-contact Voltage Tester is a volt pen with an integrated flashlight. The voltage sensor detects 12-1000V AC and indicates the presence of voltage in cables, cords, circuit breakers, light fixtures, switches, outlets and wires as well as AC voltage in doorbells, thermostats, low voltage lighting and irrigation systems. Includes both visual and audible signals. The NCVT-3 is rugged enough for any job site.