The RX gives extremely high false alarm protection with excellent tolerance to spot temperature changes from curtains and small animals. Using patented Quad Zone Logic, it is able to accurately discriminate between humans and other sources of infrared, providing reliable detection in a diverse range of applications. The attractive housing incorporates the unique Optex spherical lens design, which is not only robust, but also helps to maximize the performance of Quad Zone Logic by providing an accurate focal length for each detection zone. The RX also includes Optical Quad Technology, which uses taller detection zones divided into upper and lower areas. By detecting infrared energy changes in both areas and then coupling them, it  provides extremely accurate detection even in very hostile environments.