Thingy on the ceiling in 1938 home!!!!

What exactly are these things on the ceiling? The home is a small ranch built in 1938.

It is a alien space ship from a very small Planet.

Only one in the house? Or above other doorways? If latter - I’d say old smoke/heat sensor.

One in each room of the house above the doors…Thanks for the insight! Just curious, want to let client know what I find out.


Not sure waht it is.
Used to install older alarm systems.
while it may be a ROR detector…
it does not appear as one that i installed…
ur market may vary…

They look like old heat sensors, but a closer picture would be nice to really see them. Either that or they are Glade Stickups…LOL