A magnet and reed switching sensor for burglar alarms, normally to be recessed into doors or windows and their frames. One part contains the magnet while the other part contains the reed switch, which is normally closed in the presence of the magnet. Opening the door/window will cause the reed to open. The reed switch terminates in a pair of screw terminals, and there are a further three terminals for the security loop. Operating distance, reed to magnet: Reed closes at 13mm, and opens at 15mm.
