Interesting Hall of Famer from a set of mixed-sport perforated stamps that were made available in sheets of 25 stacked in a pad.  Manufactured in Germany, the images of boxers and baseball are similar to the W515 issue, and are reversed here so that they were properly oriented when they were applied.  The issue was a "tattoo" variety, where the cards could be moistened and applied to the skin for ink to transfer.  The intended use of these stamps accounts for their obscurity; kids do not generally save soggy paper transfers.  A high-grade example.