7939WG-WH - Ademco Surface Mount Contacts (White)

Replaced my Honeywell alarm sensor from 18 years ago, no matter size was bigger than original the instalation was easy and it worked automatically.

THESE WORK GREAT

If you need one for old school wire alarm set up, this works really well. No issue. Just a little expensive for something so simple.

They just work!

I normally use the Seco-Larm SM-200Q/W contacts when I need to replace old/failing ones but I have an instance which needs a larger gap to close/trigger.The 7939WG-WH work great for this scenario - Gap specifications are right on the mark. Installation was easy - I like the included second plate to raise the sensor a bit more so magnet and sensor spaced correctly.Great buy and will keep on my short list if I need more large gap replacements.

I purchased these to monitor my garage door status, and frankly I'm looking at getting a different brand.These arrived working, and they do still work, but only most of the time. "Most of the time" is not good enough for an application regarding security or something like garage door status.The biggest drawback is they do not work at all in cold weather. When the environment they're in is below 40-45°F, they don't function at all. They show as open constantly.The other drawback is even in good, warm temperatures (60-80°F), they will randomly (maybe once every 3 weeks) report an open status until they are cycled again.This kind of unreliability is frustrating and unacceptable for a switch that many people will use to monitor door status.Do yourself a favor and look at a nicer brand or switch to a tilt or laser sensor.

Good quality, it’s a little bit pricey

I needed these for a door that would sound a bell when when the door was open. These switches are wired normally open and when lined up with the magnet it is closed. I took the gamble hoping these were what I needed because in the discription it's not stated how it's wired. They were the opposite of what I needed and the door would sound the bell when closed and go off when opened. I put three stars only because I feel they sould add in the discription how they are wired. I didn't contact them or send them back because they were pretty cheap so I figured I might find something or someone that can make use of it.