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

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.

Was actually a NC contactor for an old school buzzer using 12v. Many others come NO without the three wires.

Great product and I will definitely buy it again because there is no alternatives.

this shipped really fast worked perfect and was a more heavy duty design than the one it replaced.

Nice unit, solid construction

I installed two of them on my garage doors in series with my thermostat to turn off the garage heater when the doors are opened. The install was a breeze (used the black and green for n.c.) and they work flawlessly. The pieces seem to be of pretty good quality, and I assume theyll last for years. These are cheaper elsewhere, but without prime shipping.

I have 4. Two can be wired different. Either n/o or n/c depends on which wires you use. They all work great.

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

Extremely good quality. This is a robustly built product. I have two in service. Installed with no issues. Flawless operation. Good range of detection l, which eases installation.

Its a magnetic switch and it works. What more can I say about it. I am very pleased with it.