WIW six pack air cleaner

I have a six pack air cleaner that I’m trying to identify/find a fair selling price.

I have struck out looking online for a similar one. I’m thinking it may have been fabricated. The only markings I see is a “R” near one of the holes in the lid.

I believe it is aluminum as it’s non magnetic. Approximately 1/4 thick lid and lower.

Any help/opinions are appreciated.

TIA