IOS-DSR Commercial Grade Self-Adaptive In-Wall PIR Occupancy/Vacancy SensorThe passive infrared sensors work by detecting the difference between heat emitted from the human body in motion and the background space. The sensor switch can turn a load ON and hold it as long as the sensor detects occupancy. After no motion is detected for the set time delay, the load turns OFF automatically. The sensor switch has one relay (equal to single pole switch), it also includes Auto Set and Walk Through features. Since this device