The Paradox 476PET is an analog, single-optical passive infrared (PIR) motion detector with pet immunity for pets up to 18 kg (40 lb). It features Paradox's automatic pulse signal processing and automatic temperature compensation for reduced false alarms and maximum reliability. Features Immune to pets up to 18 kg (40 lb) 11 m x 11 m (35 ft x 35 ft) and 15 m (50 ft) center beams with 88.5° field of view Extremely high EMI and RFI rejection PCB uses only surface mount components Solid state relay Patented automatic pulse signal processing Automatic temperature compensation Metal shield provides maximum protection against EMI and RFI signals Dual element sensor Anti-jamming switch