The document describes the Passive Infrared Detector RX-40QZ. It uses Optex's patented "Quad Zone Logic" and "Optical Quad Technology" to divide the detection area into multiple zones and detect infrared energy changes in both upper and lower zones. This provides extremely accurate detection of humans while minimizing false alarms from temperature changes or small animals. The detector also features a durable design, easy installation, and temperature compensation for stable performance in various environments.