Can anyone ID this found object part?

I'm building a Blorgon and am trying to figure out what the black parts under the eyes are made of.

 

its a weird one, they sort of look like the rings under the plate on a gas cooker ?

 

Looks to me like parts of a drop ceiling vent diffuser painted black...

http://www.madehvac.com/round_ceiling_diffuser_B.htm

 

What´s the size?
Looks like the top sections of those clear salt´n´pepper mills on a large sink-cover

Markus

 

The eyes are shower handles, for size.

 

My money would be on a lamp shade holder, the part that sits around the light globe.

 

I think gunnerk nailed it!

I have those in my home and they look exactly the part!!!

 

What model are those? I looked all over and didn't find any one only one interior circle

 

http://www.homedepot.com/p/TruAire-...-SearchPLPHorizontal1_rr-_-NA-_-202647098-_-N

Closest I could find so far from an actual retail source, still checking others.