SM-226L-3Q Seco-Larm Overhead Door Mount N.C. Magnetic Contact w/ 3 Wires for N.O./N.C. Applications (One Pack)

Works great if you do better than me and wire it correctly the first time. Thanks to whoever put the following out there: When the door is closed, there is continuity between Black/Green When the door is open, there is continuity between Black/Red

I have not installed this yet but I have tested it. It appears well made and functions as I expected it to. This switch has the ability to control two functions with NO and NC positions. I plan to use this for my garage door to tell if it open or closed (we have been known to leave the door open all night). The two contacts will let me have a red light if the door is open and a green light if it is closed without using a relay in my DIY indicator panel. This also lets me know of any faults because one light will always be on. That makes for the minimum of circuitry in the panel. I also found a magnetic switch with the same function for the man door.

Well made. Fast Delivery. I mounted it over my garage door on the wall and the Magnet bracket to the door. Will last forever up there. It has a strong magnet and activates when the Garage door opens an inch. Hooked to to a low volt LED light inside the hall leading to/from garage. Lites the way! And warns if garage is ope.

Excellent product. Far better than the run of the mill magnetic switches I first tried. These are very rugged and well made. I highly recommend them.

It works on my garage door. Now I can tell when it is open. Good Product.

Needed for a normally open circuit on a gate alarm . Works fine . Just installed so dont know how long it will last but looks well sealed from moisture. Looks like a good product

This worked great on my new garage door. I use it to indicate if the door is open or closed on my detached garage in the house.

Arrived on time and in perfect condition. Easy install.

Great product for the price

This is exactly what I needed for my garage door sensor. I had tried a simple reed switch, like one would use on a window, but it just wasnt up to the task. This item is much hardier, and the results are more predictable - meaning no more false readings. I mounted the switch at the top of my overhead door. Because of limited mounting surface on the wall and clearance requirements on the door, I was not able to line up the magnet with the switch. But even with at 50% overlap, it reads correctly. If you are setting up a door sensor that you want to work well for a long time, this is the switch you need.