(3-16-20 comment below)

This is a great tee, and it works perfectly!  By turning the pink plastic nut on the threaded stem of the tee, the golfer could adjust the nut up or down. By doing so the golfer could set the exact distance the tee could be stuck into the ground every time. Consistency—that's what the game is all about, right?! 

Measureing 2 1/8" in total length, this tee is in great condition.  The pink nut fits the threads on the stem perfectly, and moves up and down the stem with the proper amount of resistance.  Because this nut/tee were not made with the highest engineering (its an old plastic tee, after all), the nut is not perfectly square to the stem. 

3-16-20:  A few other things about this tee.  The plastic pink nut is not rigid or brittle, as brittle plastic would be more likely to crack upon impact with a club.  Instead, the nut is pliable plastic. The outer rim at the bottom moves inward easily when pinched between two fingers.  The stem is threaded the entire distance in order to allow the nut onto the stem and to move freely up and down the stem to achieve whatever fixed tee height the golfer wanted.  The head of the tee holds the golf ball in perfect position.  The ball does not bottom out in the cup of the tee nor does the cup provide undo extra space. 

Plastic tees were never sold one at a time.  Consequently, the auctioneer believes that this tee was originally sold in a group of three or four or six, and that these particular tees came in a clip of sorts that would hold the tees until it was time to use one.  The two "ridges" of plastic just under the top of the tee are identical, they are open at each end (see the added images.) These "ridges" could easily serve as the means whereby this tee would fit into a corresponding flexible clip that would open and then close around the tee when the tee was placed into the clip.  The clip would be open on one end so the tee could be easily pulled out when it was needed. 

One final point.  Because this tee has never been seen by the collecting world before, it can be said that it is not a tee at all, that it was originally made for some other purpose.  To the auctioneer, however, everything about this object says it is a tee and was used as a tee—including all the old, dried dirt located up in the underside of the hollow pink nut (and on the exterior of the underside of the head of the tee as well).  See the added image.