Door/Window Sensor allows you to monitor any door, window, or other open/close object in your home. When the object is opened, the battery-powered sensor triggers your security console to immediately sound the alarm, activate the voice dialer, and flash the lights. Door/Window Sensor consists of two components: the sensor and the magnet. The sensor installs on the door/window frame, and the magnet installs on the door/window itself. When the door/window is opened, the two components separate and trigger an alarm.