Magnetic alarm contacts are the first line of defense when it comes to your security. They are inexpensive, very reliable and the BS-2021 is simple to install and supports a common 2 wire alarm installation.
The WINN security products is a professional grade surface mount magnetic alarm contact designed to support surface mount applications in security system installations.
In a closed-circuit system, the electric circuit is closed when the door or window is shut. This means that as long as the door is closed, electricity can flow from one end of the circuit to the other. But if somebody opens the door, the circuit is opened, and electricity can't flow. This triggers an alarm.
A door/window contact is a switch that can indicate the opening of door or window. All door/window contacts, no matter how sophisticated, operate on the same principle. The switch is mounted to a door or window and is held closed by a magnet attached to door or window frame. When the door or window moves away from the magnet, the switch opens. The alarm control panel knows if the contact is open or shut, and keeps track of the doors and windows.
Dimensions: Contact: 1 1/4" X 3/8" x 3/8"