The Honeywell evohome Security Door and Window Sensor DO8EZS is a wireless magnetic door contact and is part of the wireless acessories range. Thanks to a range of over 2000m in free field the wireless door contacts can be installed with ease. The use of a special radio frequency provides improved resistance to interference. If a window or door is opened or left open the sensor will alert you. The compact magnetic sensor has a battery life of five years for long-lasting protection.