Alarm contacts are one of the simplest forms of alarm sensor. This device detects a door (or window) being opened. Jade Alarm utilizes the new Magnasphere anti-tamper magnetic sensor. Other sensors are defeated with the introduction of an outside magnetic. Magnasphere sensors are impervious to this type of attempted defeat. Magnasphere contacts are identical in appearance, but it is what is inside that counts! Jade Alarm has standardized upon this sensor for this reason. Jade Alarm, unlike many other companies, utilizes built-in supervision electronics. Attempt defeat of the alarm circuit results in the thief being detected – even during the day!