MC-31 Wired Surface-Mounted NC Magnetic Door Window Contact Sensor Alarm Reed Switch, White, Pack of 5 with 20 Screws

Ok. Let’s face it that I know nothing about an alarm system. I have an ADT system and a construction worker accidentally broke this small sensor at my basement door. Well after 2 hours of waiting, 4 transfers, and horribly exasperating experience with ADT and so solution. I simply looked on the Amazon for something that looked similar to me and I found this part. The order arrived quickly, it was simple to attach, and it works perfectly. I’m still planning to change from ADT because it’s just terrible.

They are good but I ordered wrong one This one when door are closed they on . So order what you need

I received five sensors. They are not sealed so water and moisture ingress would be a problem over time. But that's actually irrelevant because not a single one worked from the jump! I connected a seemingly identical old sensor I already had from another manufacture to some existing alarm wiring and it worked flawlessly. Then I connected each of the five new ones from this package, and every single one either didn't work at all or it was infuriatingly inconsistent! It would show closed then I'd take the magnet away and sometimes minutes later the sensor MIGHT show open, if it ever did. Then I'd bring the magnet back and sometimes it would close, other times nothing. SEVERE quality or design issues. Save yourself the headache and DO NOT BUY!

When our lower level of the house was re-modeled, the contactor did not save the contacts from two door moldings for my Ring and Insteon sensors. I got these just for the contacts and they work fine for my Ring and Insteon open/close sensors.

Good