This pole was specified for use by The Pure Oil Company for their primary "major" signs at Pure stations beginning in the late 1930s and lasting through the Union 76 rebranding in 1970, and for many years afterwards, with either fiberglass 76 panels over the porcelain Pure, or with, rarely, porcelain 76 signs. These poles were not a Pure exclusive - Tydol/Flying A, and Lion also used them, complete with the fins. Complete assemblies have the fins on the light conduits, as well, projecting front and back. As far as I know, these were not used west of the Dakotas by any company. There are some left along the roadsides here, but not as many as just 10 years ago.
Petroleum Collectibles Monthly