3sets White Iron Door Recessed Wired Security Window Door Contact Sensor Alarmmagnetic Reed Switch,Magnet Near - Connect Circuit, Magnet Away - Break Circuit

Needed a door light switch but didn’t want to have to chisel a rectangular hole for a Home Depot switch so found these on Amazon. Worked great and just have to drill a hole for them.

These work as expected. Good value, not worth spening more for a basic reed switch like this. Not much to get wrong. Both sides are fully potted, so should last a long time even in weather.. The magnet housing can be trimmed shorted if needed, there is probably 1/4" of empy space at the end. Simple install, just drill two holes and push them in. If you want a precise position, say for indicating whether a door is fully latched, you will need to offset the magnet as the magnetic field extends beyond the housing and will trip the reed switch before they are lined up. In my experience, these need to be offset by roughly one unit width; test with a muktimeter before install. Also, they seem to have enough reach to work across a half-inch gap.

This was the closest contact I could find that was close to the original ones installed 25 years ago. Had to trim the wiring down to fit, and they are perfect. Very happy.

These work ok if conditions are just right. The magnets are weak and will only tolerate a small gap before not working. The price is good, I just wish they had used better magnets.

Worked great

Easy mounting

Was not able to get it working.

Their definition of NC and NO are reversed. Also, they will not break a load of 12Vdc @ .2amps. Complete garbage and waste of money.