1940's-? White's Card Room Equipment Co., Cincinnati OH;

Rigdon and Co., Cincinnati OH (they referred to it as "'Lazy Diamond' Registered Monogram Checks"

Herman Baron and Co., NYC (in 1960 and 1965 catalogs; they say "The design is non-duplicate, exclusive with us...").

I also have an Arthur Popper Games, Inc., NYC, catalog (1940's-1950's) that also hails it as their "non-duplicate, exclusuve... ... Protection Check."....