Yohii 5Sets Recessed Security Alarm Contacts Door Window Sensor Magnetic Reed Switch White

I am using these to create a custom computer "game" interface where an object is slid around on a table top its position triggers game events. I would describe the switches as Normaly Open (NO) when no magnet is nearby, and the magnet closes the switch. The switches are activated (closed) when the magnet is about 1/2 an inch away, but since i need them to operate from about 3/4 of an inch away, through the table top, I am simply using a bigger/stronger magnet. Working great so far!