Edward Tools Harden Pro Non Contact Voltage Detector is an electrical volt detector pen for AC voltage of 90V to 1000V. Simply press the on button and a green LED light will indicate that the pen is operating. Place detector near power and a bright red LED light will flash while a loud warning alarm will buzz indicating there is power. After non use for 2 minutes the electrical tool will auto power off. A flashlight LED on the point can light up any dark work space for safer and more convenient work. Edward Tools Harden Pro Non Contact Voltage Detector comes with a lifetime warranty.