Expand your Smarthome SecureLinc Wireless Security System coverage by adding extra motion sensors. Unlike other units, this wireless PIR is smart enough to tell the difference between burglars and your pets by triggering events only if the culprit weighs more than 85 pounds. The 85-Pound Pet-Immune Motion Sensor will work with any SecureLinc wireless security system. With a 90-degree coverage area of 40 feet, this fully supervised detector will keep your home secure when you're not around. Upon detection of an intruder, the on-board transmitter instantly sends an alert to the wireless alarm system. With its superior transmission range, this highly accurate unit is able to differentiate between real threats and large pets, allowing your animals to move freely while still ensuring the security of your home. The 85-Pound Pet-Immune Motion Sensor features patented technologies such as Digital Signal Processing (DSP), "True Motion Recognition" (TMR) and 3D "Target Specific Imaging" (TSI) Cylindrical optics. A 40-pound version of this pet-immune PIR sensor is also available.