20 Pcs Brown Wired Door Contacts Surface Mount Nc Security Alarm Door Window Sensors.these Door Contact Position Switches Dcs Work With All Access Control

Manufacturer	Unbranded
Model Number	B077Y4VR22

This is a 20-pack of surface mount door contact switches that are used with commercial or residential card access systems and security burglar alarm systems. The door position switches operate with a built-in magnetic reed switch that closes when the opposing magnet comes within " of the door sensor. When the door opens beyond the " point the door position switch will switch from a closed signal to an open signal. When this happens the access control system or alarm system will sense the change in continuity and will know that the door or window has been opened. When the door or window shuts, the door sensor will notify your security system that the opening has been closed.

These are the door contact sensors that are in use with any and all commercial or residential card access systems as well as all security burglar alarm system. The door position switches operate with a built an internal magnetic reed switch that closes when the opposing magnet comes within " of the door sensor. Hence when the door opens beyond the " point the door position switch will switch from a closed signal to an open signal. When this happens the access control system or alarm system will sense the change in continuity and will know that the door or window has been opened. When the door or window shuts, the door sensor will notify your security system that the opening has been closed.