Intruder Alarm Door contacts.
An Intruder alarm contact is used to monitor and protect a door or window that opens. Contacts usually have 2 parts. A reed switch is contained in 1 part while a magnet is located in the other. Contacts are available for flush or surface fitment. Flush contacts are usually fitted inside of the door itself. Surface contacts are located on the surface of the door / window. Other types are available for roller shutter doors, safes and for use in heavy duty applications