The Santronics AC Sensor is UL listed and manufactured 100% in the USA. Handheld device for determinig the presence or absence of 50-1000 volts in insulated wires, wall receptacles, fuses, junction boxes, switches,and other voltage carrying elctrical systems. Determines defective grounds, reverse polarity, and induced voltage. No contact is required for operation and current flow is not necessary to locate voltage. If AC voltage is present, the LED light in the tip will glow cherry red. ***Get your company logo/name listed free for quantities of 24 or more*** contact us for details.