Early 1970,s GM cars had those cleaners , they had a filter inside the air cleaner. About 3/4 x 2" filter . I believe they attached to a 2nd pcv valve or something like it and were usually oil soaked. Your best bet as previously mentioned would be to find another complete breather.
I believe you are referring to something very different. We are referring to the ring that is glued to the inside of the air cleaner. It looks like a second air filter.