Optex offers unprecedented dependability in detection by integrating state of the art PIR and microwave technologies. The MX-40PI combination detector features a patented "quad zone logic" which demands detection across multiple zones before triggering an alarm. As a result, the MX-40PI is able to guarantee false alarm immunity from 100 pound animals/pets and immunity from other smaller disruptions such as movement from curtains and heating vents. Its sphere shaped lens design allows sharp, precise detection zones to be maintained without distortion for advanced reliability. The MX-40PI introduces a pre-installed "anti-crosstalk system," blocking interference from matching microwave frequencies in a given area. It also sports a microwave range selector and uncomplicated wiring knockouts for easy installation.