Update 4-13-23:  Yesterday, I changed this listing to state that it was a dark green mold.  It certainly has a dark green hue to it.  However, this morning I received an image of an actual green Keystone mold, and it's clearly green. Consequently, the mold being offered here is the black version as initially described.

Produced by the Keystone Mfg Co, of Chicago, Ill, this black Keystone sand tee mold was covered under a 1928 patent issued to L.E. Johns.  The mold itself is made from bakelite and includes a spring-tensioned plunger.  After loading up the cup with moist sand, the golfer need only place the mold on the ground and push the button on the top.  This would to eject the sand as a ready-made tee.

A copy of a Keystone Moulder advertisement is included with this ball. There is also an orange and a modeled Keystone Molder in this auction. All are in perfect working condition