Make your home, office or any other place secure with the Chamberlain wireless alert system that comes with a remote sensor-transmitter and a receiver base. The sensor has a 120° wide angle coverage and detects human and vehicle movement up to a distance of 30" while it ignores animals. With its adjustable sensitivity controls, you can prevent false alarms. The sensor transmits a signal to the receiver that can be placed up to 1200" away from the transmitter. This wireless motion alert system"s receiver can be connected to 4 different sensors (sold separately) to simultaneously monitor several locations. Each time the alarm sounds, it activates a 10 amp switch that can be linked to an existing alarm system, siren, light or auto-dialer to complete the chain. This home security system"s sensor is waterproof, so it can be used in your driveway or patio. The sensor runs on 4 AA batteries while the receiver needs a 9V battery.