The Greenlee WM-12F (52083986) Watchman 12-Pack Kit with Work Area Voltage Detectors, Fence Mount Brackets and Carrying Bag, 2400V AC and above, uses WAVi voltage indication technology to detect strong electric fields surrounding high voltage conductors and power distribution equipment. It is typically placed in the vicinity of power lines or high voltage equipment. The Watchman provides an extra level of safety for trained personnel working on or near high voltage systems.

The Watchman Area Voltage Detector works by sensing the presence of the electric field surrounding anything that conducts high voltage electricity.

Spinning lights indicate an electric field and nearby energized conductor. The Watchman Detector has a power and self-test button on the top of the unit to verify battery power and proper functioning of the device. The short flashing lights "heartbeat" indicate that the Watchman Detector is on, checking for the presence of high voltage electric fields.

The Watchman Detector can be placed on the ground. The Detector will detect energized high voltage conductors on all sides and above it.

The Watchman Detector can also be applied to a fence or other similar structure using the included hanger brackets. When applied to a metal fence, the Detector will only detect conductors on the side of the fence it is hanging from. The Detector can be applied directly to a bare or insulated overhead conductor up to 35kV also using hanger brackets. In this application, the Detector will provide a direct indication of the presence of voltage on either the conductor to which it is applied or on other nearby conductors.