On the left is a typical Hemingray CD 164. On the right is what appears to be a retooled H.G. Co CD 164  leaner with a wider squared off upper wire groove ridge resulting in a slightly different shaped dome. The front crown also has a very large blott out on the right side resembling a diamond shape with a raised bump in the middle....the blot out kind of looks like an all seeing eye.
I am wondering if in a former life the mold that produced this insulator was originally embossed as a Diamond or Prism insulator?
Another similar 164 variance posed by John Sheehan