Here is a brand new resin facsimile replacement knob for a vintage embalming machine.  This was molded from an original knob taken from a Turner Porta-boy unit but may be used on other models.  It is cast in urethane resin with a marble filler and has been painted black.  It measures approximately 2” in diameter and about 3/4” deep with an approximately 1/4” diameter hole in the back.  You might want to mount it by adding a little epoxy adhesive to your unit’s control spindle.  I have multiples of this casting available so let me know if you are interested in additional knobs.  See photos for overall condition and ask any questions you may have.