If you rely on a security system to monitor your home or business, you don't have to wait until an intruder breaks in to protect your property. Install the Outdoor Dual Beam w/Piezo Sounder motion detection system, and you'll protect your building's exterior by detecting intruders before entry is attempted. This pair of motion detectors can also provide a deterrent with the system's built-in audible alarm indicator, which sounds before break-in occurs. Set up multiple sets for added security.The Outdoor Dual Beam w/Piezo Sounder includes two units that send IR beams to each other. When the beams are broken, the motion detectors send a signal to your alarm system, and their internal 70dB sounder is triggered for 15 seconds. Safe for both indoor and outdoor use, the Outdoor Dual Beam w/Piezo Sounder is completely waterproof and has built-in light reduction filters for use in any weather. A tamper switch signals the alarm panel when the cover is removed. Additional features include an indicator LED that illuminates in alarm conditions.