2X Magnetic Reed Switch Normally Open Closed NC NO Door Alarm Window Security/Magnetic Door Switch/Magnetic Contact Switch/Reed Switch,DC 3V to 12v Lamp（White）

The price is reasonable, it's easy to install, and versatile enough with systems that require either NO or NC. It's hard to say how long it will last since I just installed it a few days ago. This is a replacement for a similar item and manufacturer that lasted a whopping 28 days before failing. I'll give this one the benefit of the doubt for the time being and adjust the rating and review as necessary...

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 found this magnetic switch and it was more-or-less perfect for my application, but I couldn't help but notice all of the reviews of melted units. On further inspection you'll notice that many of these reviews detail misuse of the product by passing far too much current through it, for example to a lightbulb. This item uses a lightbulb as an example but explicitly says it should run to some sort of panel. This is a switch meant for powering a relay that can actually handle the current of your application. This is a switch for a signal, not for power. This will work great for something like an Arduino, but it will not for powering truck lights. Be warned that this is totally a Chinese wholesale product and you probably cannot pass through as much current as it says, but using it modestly will yield the intended result. Realistically you should not pass through 0.5A. You don't need much for a signal.

Great price way cheaper than rv branded part and does exactly the same job

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.

If you are using these for doing fun little projects, these are great little reed switches. If you are wanting to use them to notify you of a window or door opening to trigger a home alarm or some other automation, these are simply not good enough. I originally bought these to alert me when my shop bay doors were open, but they just weren't strong enough to give me what I was looking for. I ended up going with some beefy industrial reed sensors for that project and they are still working a year or more later. I still keep these little reed switches around to play around with other home automation ideas and they work great for proof of concept type projects.

This magnetic switch will work for either normally open or normally closed circuit. Our RV came with a new set of steps but had the wrong option magnetic switch to open and close when the ignition switch was on. This was any easy fix.

Both switches worked out of the package. I used double sided adhesive tape to mount the switch in my mail box. It worked for about a week then I got a false alert. It seems that the adhesive pulled the back panel off of the switch and now when it should show open, it instead has a resistance of about 2000 ohms, hence the false alert. Also the NC terminal is continuously closed with or without the magnet. I installed the second switch but immediately ordered a new switch from another company in anticipation of another failure. This switch is a great idea but a poor implementation.

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.

I used these for confimation of my garage door being closed in my home automation setup. They work consistently and the distance that the two pieces can be apart is actually more than I expected. Overall they work great and are a good price.

Just as described

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.

The first switch worked like it is supposed too. Second one did not work.