So I came upon this 1922 patent.
https://www.google.com.gi/patents/US1438553 .
Looks like it matches the air cleaner that I posted in #1.
You can see by the attached photo of the other air cleaner tag that United Mfg holds (held) the 1438553 patent. The air cleaner shown is for a Model T.
I don't think it's unreasonable to assume that these air cleaners were made by United Mfg well into the 1930's, maybe even up until the war..
Previous posts about these air cleaners being used on 1920's cars were right. My guess that they were used for vintage agriculture equipment applications was incorrect.
I love finding out these little historical tidbits
