White plastic type works with most.

Look good and easy to fit

Worked well

The contacts are well constructed however since fitting , our alarm system has been upgraded so I cannot vouch for there longevity

This unit works OK, however the wires from the reed device are short and either move out of contact or can break the fragile glass envelope when connecting external wires. It is not an ideal termination for the reed relay.

We have just had new UPVC front and back doors installed. It wasn't until the people doing the back door said "What do you want us to do with this door sensor?", that we realised we actually had door sensors, as they were of the embedded at the top. As an aside, our burglar alarm system had never worked properly, but despite being an Engineer, I could not figure out why. On the above revelation that we had door sensors, all became clear ... the previous owners had replaced the front door with a UPVC door and the sensor was just chopped off and the sensor wires permanently connected. The end result was that the alarm system could not detect the person setting the alarm going in or out of the house. However, this revelation posed a problem - how to fit new sensors, to our lovely new doors, without compromising the guarantees that came with the doors. I don't know whether I have compromised the guarantee, but I decided surface mount contacts would be less of a compromise than embedded sensors. I also decided I wanted contacts that would take all the wires from the cable (four in my case, I thought it was five, but got it wrong). Anyway, thought the above would 'fit the bill'. It meant only 2 small screw holes into the door panel and 2 for the reed switch above the door panel, which really should not compromise door operation! They seem to work fine. The technical info. states max 20mm separation, which via the use of a multimeter, seems to be about correct. I've got it set up with about 10mm to be on the safe side. Had to put some pilot holes in the UPVC door, as the self-tapping screws would not bite into the plastic by themselves, but very easy to fit. The silver screws are for the reed switch, the other brass screws are for the left over wires. Package came very quickly via a jiffy bag in the post (not unexpected). Make sure of your sizes, as to my mind they looked a bit bigger than I thought they would be, but it did give me more room for extra slack in the connecting wires.

suspected problem with burglar alarm was due to faulty sensor, bought these to replace. easy to wire up and fit and works fine now. had to look online for reassurance and clarification on which terminals to connect.

Need replacing

I wanted replacement door sensor for our new white UPVC door as the old cases had yellowed with age and varnish. This was a direct replacement so switching over was easy and works treat even with a larger than previous gap between the reed switch housing and the magnet locations. I had previously checked the maximum achievable gap using a multi-meter and slowly separating the 2 housings and checking when the reed switch contacts finally opened. A pilot hole was not required to fix the housings, just s bit of initial force to get the screws to bite into the top of the door and frame.