Monitor movement around your home and keep your family prepared for visitors, welcome or not, with the powerful Skylink Wireless AAA+ Indoor/Outdoor Motion Sensor. The sensor"s wide detection range allows monitoring of large areas, such as your front/back yard or driveway. Rolling Code Technology Every time you press your remote transmitter to turn the security system on or off, a code is generated which is recognized by the receiver that in turn performs the desired function. With most security systems, there is only one assigned code. Whenever the remote is pressed, it generates the same code, making it vulnerable to code grabbers who use electronic scanners to steal the code. With rolling code technology, each time the remote is used, it generates a different code which can only be recognized by a rolling code receiver. Even if an electronic scanner picks up the code, the next code will not be the same, and the receiver will not recognize the old code. As a result, security systems with rolling code technology are increasingly safe and secure. Note: Requires the Skylink AAA+ Control Panel (sold separately).