Advanced PIR1680 series passive infrared motion detectors exemplify NAPCO sensor technology's innovation, increasing dependability without compromising intruder catch sensitivity. For applications where animal/pet immunity is key, the PIR1680PT supports 65lb. (29kg) pet protection within its 45' (13.7m) range. Or, the original model PIR1680, has a 50' (15.2m) range and offers nominal 20lb. (9kg) animal/rodent immunity. Outstanding false alarm rejection in both models is made possible with their advanced microprocessor that has been embedded with a library of valid and false alarm signal signatures - enabling the PIR to differentiate intruders from animals and other traditional false alarm sources. In addition to proven intruder-detection circuitry, these units also feature a built-in temperature sensor - at no additional charge - so you can provide traditional security, as well as climate security from heat and/or freeze damages, when HVAC systems fail, before pipes burst or decor, pets or perishables are ravaged by heat extremes, otherwise left unchecked.