It's from Jameco, it's about 8.5" across, and it's plastic. I'm not sure what it's for (it was left by the previous owners) and looking at the Jameco website didn't narrow it down. It looks very specific.
If you have a way to use it, it's yours! If you don't need it but know what it is, that would help me write a better description so it can get to someone who can us it.
Fair Offer Policy applies