I don’t have the exact model to hand, but they are a super discrete little thing in the ceiling. I can get the exact model later if you want.

It does motion in 3 directions using infra red, and gives you light levels and temperature as well.

They can sense really damn far, and actually I had to turn most of them down in sensitivity to make them useful.

I use the same sensors for triggering the alarm system. They look way more attractive than those ugly corner sensors most security systems use.