Ademco Honeywell 5890PI Wireless PIR motion detector with pet immunity - 35' x 45' (10.6m x 13.7m) coverage pattern, Immune to pets up to 40 lbs. Split-Zone Optics technology, for use with Q.E.D. control panels only, Up to 5 year battery life. The convenience of wireless systems extends to include pet immunity with the 5890PI. Using Split Zone Optics technology, the 5890PI ignores pets and other animals up to 40lbs., while continuing to detect even crawling intruders. Split-Zone Optics: splits each into two stacked sub-zones. Each sub-zone is the same size as the original, but only has about half the sensitivity. To generate an alarm, target must intercept both sub-zones simultaneously. A human target is sufficiently large enough while pets up to 40 lbs. remain undetected