Expand your Smarthome SecureLinc II Wireless Security System coverage by adding extra motion sensors. Unlike other units, this PIR is smart enough to tell the difference between burglars and your pets by triggering events only if the culprit weighs more than 80 pounds. With a coverage area of 30 by 30 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 SecureLinc II Wireless Security 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. 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. Features patented technologies such as Digital Signal Processing (DSP), "True Motion Recognition" (TMR) and 3D "Target Specific Imaging" (TSI) Cylindrical optics. If you have pets that weigh less than 80 pounds, use the 40-pound version.