For your reference are the two mold variants in the California, CD 152, Hoopskirt insulator. The green on the left is the more common mold type. Notice the fuller, more squarish dome, the shoulders on the skirt and if you could see the smooth bottom you will notice it is rounded. The blue Taper Top mold variant on the right has a smaller tapering dome, no shoulders on the skirt and if you could see the smooth bottom upside down, you will notice that it is flat, sloping downward, inward. There is also a rounded bottom version of the taper top.