RX-40PI pays no attention to false alarms caused by spot temperature changes like small to medium sized animals, air conditioners, or windblown curtains. Using Quad Zone Logic, the RX-40PI puts together signals from its 78 detection zones areas to determine the size and precise location of its target. Its superior quality Spherical Lens and its thorough detection pattern give the RX-40PI Catch and Pet Immunity that is far superior to other single technology detectors. RX-40PI also has an insect proof sealed housing and comes with OPTEX's 5 year warranty.