Klein Tools Non-Contact Voltage Tester detects standard voltage in cables, cords, circuit breakers, lighting fixtures, switches, non tamper-resistant outlets and wires. A bright green LED will tell you the tester is working and also functions as a worklight. It changes to red and warning tones sound when voltage is detected.Voltage tester provides non-contact detection of voltage in cables, cords, circuit breakers, lighting fixtures, switches, non tamper-resistant outlets and wiresVolt pen with high intensity, bright green LED that indicates the tester is operational and aids in illuminating the workplaceWhen voltage is detected, a high intensity, bright red LED illuminates and a warning tone soundsDiscreet digitally controlled on/off power buttonAuto power-off feature conserves and extends battery lifeMicroprocessor controlled low-battery indicator and tester shutdownCAT IV 1000-Volt safety rating provides expanded operation and protection