KD sand tee molds are made from thin aluminum.  They are sometimes found dented or dinged up because thin aluminum is not the strongest material.  This example, however, is in pristine condition, with the spring loaded plunger still in perfect working order. After loading up the mold with wet sand, just place the mold on or just above the ground and push down on the top of the tee.  The plunger will move down, dislodging the newly formed sand tee onto the ground.  Then place the ball in the small depression left in the top of the sand by the slightly convex base.

The top of this plunger on this mold is marked "K-D Mfg Co, Lancaster, PA" and the bottom of the plunge inside the cone is marked "Pat Apld For"  This references the US Patent (No. 1,616,908) issued on February 8, 1927, to Harry W. Kulp, the inventor of this sand tee mold. Most of the K-D molds are marked with the actual patent number.  This one was obviously made before those.