The Greenlee VW-20H (52068928) V-Watch Personal Voltage Detector with Lanyard Case detects the strong electric fields surrounding high voltage conductors and power distribution equipment. It is a small pocket size device worn on the outside of the clothing or other protective gear by users operating near power lines or high voltage equipment. It provides an extra level of safety for personnel trained in the use and application while working on or near high voltage systems. The detector is supplied with a tough carrying case made of black shielded material.

The V-Watch Personal Voltage Detector works by sensing the presence of the electric field surrounding anything that potentially conducts high voltage electricity and sounds an alarm. It measures the strength of the electric field; a higher voltage or stronger field will cause the detector to alarm from a greater distance.

The V-Watch emits a series of loud beeps and flashing lights when an electric field is first detected. The beeps and flashing lights increase in frequency as the user approaches the source of the high voltage electric field. A steady tone indicates very close proximity to high voltage and the need for extreme caution. This variable beeping rate helps the user to determine if they are approaching the high voltage source or moving away from it to safety.

The detector has a self-test button to verify battery power and proper functioning of the device. It will also sound an alarm to warn the user of a low battery. Whenever the detector is being used, it is always on, checking for the presence of high voltage electric fields. A standard 9-volt alkaline battery powers the unit for about one year.