Berylliim Oxide Beryllia Ceramic disk set 1" dia. and thermal mirror mount

Description

Beryllium oxide disks, two for one price.
Unusual disk with concentric rings for mirror mounting?  Each ring is slightly raised above the others as they get larger dia. I think this is so you can mount mirrors of different standard sizes.
The rings are 0.25" dia.,then 0.5", 0.75" and 1" dia. with the O.D. 1.14" Dia.
Due to the thermal properties of Beryllia, I think this could be for drawing heat away from high powered laser mirrors and transferring it to the .625" dia. post on the back which would then be heat sinked. The post protrudes about 1/4" out from the back. I'm guessing you would glue the mirror with a thermal adhesive.
but then, this could be for something else. You decide.
The other included disk is 1" dia. x 0.123" thick
I combine ship to keep costs down.
See my alternate store by seller "mebe3d" for many more photonics items.