Mt Washington Eggs

Mt Washington produced three different variations of their egg.The most coom one found is on the left with the typical screw on top onto moulded threads in the glass.
The next two pictures are what is called an Ostrich egg and has a press on top with tiny prongs that holds it in place. (same as thier Fig shakers)
Right is a variation that in slightly larger in circumfrence and has a two piece top. There is a tiny applied collar attached to the piece and the top screws onto that.