?Features: AC non-contact voltage testers are easy to use just touch the tip to a terminal strip, outlet, or supply cord. When the tip glows red and the unit beeps, you know there is voltage present. Electricians, maintenance, service, safety personnel, and homeowners can quickly test for energized circuits in the workplace or at home you can check the live wire voltage while starting this tester if tester gives the beep sound it means supply available if tester does not beep sound so it means supply not available you can easily find any fault. ?Specifications: Material: ABS Plastic Color: Yellow & Black Item size: 152*23*15mm Test Voltage Range: 90-1000V AC Safety Rating: CAT II 1000v Frequency Range: 50 to 500 Hz Powered By: 2 x AAA Batteries (Not included) 1 X LED Light Voltage Alert Pen