What is this?

My client asked what the little detector was, it was installed in a home built in 2000. I did not want to guess so I said I would ask my guys. What is it?

Photo electric smoke detector

Typically installed as part of a home-security system.

Thanks!

It’s a smoke detector. It’s installed in some buildings and offices for fire safety precautions.

Exactly…
sold and installed many of them years ago…

Smoke detector or a HAD.

yes its a smoke detector.