... Safety Rating: CAT II, 1000V Blue Non-Contact Voltage Detector Pen AC Volt Sensor Tester Alert 90~1000V LED, YFT397A Trade ... , circuit breakers, wall sockets, junction boxes, fuses, etcSmall and compact pen design for easy carryingTest Voltage Range: 90-1000V ACFrequency Range ... electric industry usersHow to use: touch the wire with the pen tip.If the red indicator lights up, it means voltage exists ...