5pcs 433MHz gsm Wireless Door Sensor wireless Window Entry door Detector Magnetic Contact For Home Alarm System

These sensors are used to protect the opening of both doors and windows. If a burglar opens the protected door or window, a magnetic switch inside the sensor, will trip, which sets off the security system. Install one at every entrance to make sure your home is protected. Each sensor is supervised (self-checking) for professional reliability and offers you choice in design and performance.