2X Magnetic Reed Switch Normally Open Closed NC NO Door Alarm Window Security/Magnetic Door Switch/Magnetic Contact Switch/Reed Switch, DC 5Vto12V Light (Black)

I use this switch with warning lights on my garage door. I install a 120v to 12v transformer in my garage next to my garage door opener. Then install two 12v lights in my room connected to my garage. When my garage door is open, the lights are on. When it is closed, they are off. I can always tell if I forget to close my garage door.

I purchased this to make my own wired open/close detector for my garage door opener. The ability to use this both as a Normally Open or Normally Closed switch is great because I wasn't sure what mode I needed to have for my plan to work. So far it has worked flawlessly for me.

These come with small wood screws and appear reasonably well made. The nomenclature on the terminals is reversed - NC usually is Normally Closed until the switch is actuated, but with these, NC is closed when the magnet activates the switch. Not a problem if you know before you do your installation.

So inexpensive and such a difference. Installs in fifteen minutes and transforms your closet experience. Turns light on when you open and off when closed. Very flexible installation and ease of use! Love them!

Purchased to use with a small strip of LED lights for our RV pantry door. Lights turn on when door opened and turn off when door closed. Worked great for two weeks then failed. You can see it melted and was very warm to the touch when I removed it. See how long this second one lasts but these are very cheap. Buy something better. I bet I only had less than a 10w load on it.

Installed a light under my truck bed cover that uses this as an activation switch like a refrigerator door light. Works great, but the magnet wasn't big enough for my application. I found a bigger magnet in the garage, now I have no problems.

i like it

I chose this as it was a 2-pack, and I needed multiples. They do work, but not perfectly well. One switch works but flickers even with a low amp, low voltage current passing through it. The other sometimes refuses to work; almost as though it is either stuck open or stuck closed. On top of that, the Normal Closed and Normal Open posts are reversed.

Very frustrated with these switches. Worked on the bench with ohm meter when voltage sent through circuit switch has failed 90% of the time. Over the return time grrrr. Will have to find another and better switch maybe something local. Not happy at all. A waste of money.

A great little set of magnetic switches for a decent price. I purchased these to use in a cabinet to turn an LED strip on when the door opens and they've been working great! They feel like they are built pretty well and after using them for almost a year now I have never had an issue with them.

Would have been nice if NO and NC were clearly marked.

Tried all 3 switches and every combination with the magnets and nothing worked. Like others have said, NO and NC are reversed from the description which is easy to get around. Problem is all 3 of mine are either always open or always closed, not exactly what I'm looking for in a switch! Sending it back.

These magnetic reed switches work better than I expected; they don't have to touch the magnet to work, as long as they get within 10 mm or so.But, the contacts are mislabelled; the NO (normally open) is actually NC (normally closed), and vice versa. I used my continuity meter on them and so relabelled them before installation, and was glad I did.I used them as sensors for an appliance garage in our new kitchen; while having a power outlet in an appliance garage is now illegal in the US, it is still legal in Canada, IF the power to the outlet is automatically switched off when the garage door is not fully open. The magnet was mounted on the moving door, the switch on the wall where the door stopped when fully open, and the contacts switched a safe 24VDC circuit (power adaptor also from Amazon) to control a 20A power relay from Grainger (Functional Devices). The end result works extremely well, and made my wife very happy.The electrician who installed the system was also impressed.