These paddles are made from beech wood, rubbed with bee's wax.  They are meant to fit a newer (post WW-II) Vibroplex.  The hole spacing is 7/16 inch, and the edge hole is  sized to pass a 6-32 screw, while the inner one is sized to a close fit for an 8-32 screw.  These could fit classic Vibroplex products such the Original, Champion, or Lightning Bug or even homebrew keys.  Some adjustment of hole size or spacing may be needed in your non-Vibroplex application.  Shown in the next 2 photos is what a typical paddle looks like on an Original.  The key is not included in the sale, of course.  The next two photos show my setup for making the knobs, while the last few are of some other styles of paddles/knobs I have made, the last a custom job for a ham colleague.  Email me if you have any questions and thanks for looking!