The Extech DV23 CAT IV Non-Contact AC Voltage Detector displays a red LED with audible beeper when it indicates the presence of live wires. The non-contact detection feature allows user to be at a safe distance from area being tested when presence of live voltage is unknown. Suitable for outlets or against wire insulation testing, this AC Voltage Detector/Flashlight for non-contact detection of AC Voltage measures from 50 to 1000V (50/60 Hz). The Extech DV23 is ideal for troubleshooting electrical wiring, appliances, automotive repair and electronic devices.