Fortress Total Security Door/Window Contact

This sensor is a magnetic contact sensor for doors, windows, and other entry points. When the magnet and the sensor are separated, the sensor sends a wireless signal to trigger the alarm. When you mount one piece on the door or window, and the other piece on the frame, the sensor will activate whenever the door or window is opened. For best performance, you should not mount this sensor directly on a metal surface. The sensor and the magnet should be no further than ¼ inch apart when the door or window is closed. When applying the adhesive tape, make sure that you are mounting on a clean, flat, dry surface. A starter battery is included with the sensor, and we offer additional 23A batteries for purchase on our web site.