The GE 60-807-95R motion sensor is a passive infrared device that measures the change in temperature in an area of the room. In effect, it “sees” body heat emitted from a human body as it passes in it's field of view. This technology has been in use for over 20 years and is perhaps the most reliable method to detect intruders.
The sensor is also able to discriminate the heat radiation from an animal of 40 lbs. (no cats) or less and a human body. This drastically reduces the chance that your alarm will go off (and cause a false alarm) when a pet is left in the detection area.
Passive infrared detection
Detects movement inside an enclosed structure
Use in large rooms, narrow corridors, and stairwells