Klein Tools dual-range non-contact voltage tester automatically detects low voltage and standard voltage. A bright green LED will tell you the tester is working and also functions as a work light. The light flashes red and two distinct warning tones sound when either low or standard voltage is detected. Voltage tester automatically detects and indicates low voltage (12 – 48 VAC) and standard voltage (48 – 1000 VAC) allowing broad application. Non-contact detection of standard voltage in cables, cords, circuit breakers, lighting fixtures, switches, outlets and wires. Non-contact detection of low voltage in security, entertainment, communications, environmental control and irrigation systems. High intensity, bright green LED indicates the tester is operational and aids in illuminating the workspace. Dual range testing, select 12 – 1000 VAC or 48 – 1000 VAC. Auto power-off feature conserves and extends battery life. CAT IV 1000 V rating provides expanded operation and protection. Lightweight, durable polycarbonate plastic resin construction – convenient pocket clip. 9.8 ft/3 m drop protection. Safety rating – CAT IV 1000V. Conforms to CE requirements. 50 – 500 Hz low-pitched pulsing beeping sound, blue LED turns off and red LED blinks (Approximately 2X Per Second).