The Magnasphere® switch
One of the staples of the tools that protect our physical property is the magnetic switch. You see these switches everywhere: Doors, windows, you name it and you will find a magnetic switch somewhere nearby. When the door or window is closed the switch is near a magnet, which holds the switch closed. When the door or window is opened, it moves away from the magnet and the circuit is broken, triggering the alarm.
The devices are well-established and work well, but are defeatable by someone with knowledge, a compass, and a magnet: You use the compass to find out where the magnet is, and therefore the switch is, then put your own magnet next to the switch while you open the door or window.
There are, of course high security switches which deal with this problem, but they tend to be a bit pricey, albeit worth it if the threat is high enough.
A new approach has been taken by the folks at Magnasphere Corporation, who created a simple device that cannot be defeated by use of an outside magnet because of the needed directional sensitivity of the system: A magnet placed anywhere but at the bottom will break the circuit, rather than keep it open.
The device innovative and simple, which means the cost should be low enough to use anyplace a normal reed switch might be used, giving a good combination of low price and high protection. The device comes in several versions, including high security device (not shown), and the standard device shown above. You might want to suggest that your physical security folk take a look at these devices.