Seco-Larm SM-4601-L3Q Industrial Wide-Gap Magnetic Contact Switches, 3" Operation Gap NO/NC, Open/Closed Loop (3 Wires)

I got this as a closed door detector for my automated garage door opener. The extra wide sensor gap (it will detect the magnet up to an inch or more distant) makes installation easier and much less "fiddly".

I use these to control a 12-volt light when a closet door is opened. The switch changes state when the magnet is several inches away, which works well for my application.

I have used these wired to Z-Wave window/door sensors and to Zooz dry contact sensors. They are weatherproof methods of accomplishing automations where you cannot put a standard indoor sensor. They work both NO/NC for flexibility.

Switches like this can run upwards of $99 per unit! This was a much more affordable option for us and not a single unit was faulty on arrival. After two months of daily use, all units continue to operate without fault.UPDATE: These sensors seem to become less reliable in cold weather ( at around 30F and below. This is a temperature far above the listed -15F range). For the most part, the direction the magnet and sensor face doesn't seem to matter. However, at these colder temperatures, the circuit closes when the door opens and stays that way even after the door has shut again. Fussing with the orientation of the magnet and sensors (reorienting which side of the magnet and sensor faces up or down where they are mounted) Seems to have corrected this issue for the time being.

Will use this on my side gate to activate a light inside the house. Now If I could remember where I put it.

This does exactly what it says it does. It's a basic magnetic switch, but it's well-made, aluminum casing, very rugged, and has a wide gap that is perfect for gates, overhead doors, barn doors, etc. The cable is a 3-wire, so you can connect it in a normally open or normally closed configuration.

Hooked up for my new closet lighting.. I'm an HVAC tech, so have thorough electrical knowledge that I installed it correctly. After using a handful of times, the switch did not open (turn lights off) .

Good product works as expected, will buy again.