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Todd SchultzAnyone know what might have been inside this? Copyright 1937, 3 5/8" x 5 5/8".
 
 
I know Leader Novelty was involved with the R316s in 1929, and I think they had some non-sports issues, but this one looks like it should hold some baseball-related postcard or such.  Still, I can't find any set that could arguably match up. Any help appreciated.