This insulator is a CD 121 with an embossed Diamond with a faint vertical bar on the back. I cannot tell if the vertical bar is part of a blot out. I do not think their is a blot out on the Diamond side. The color is tough to call. It looks like a light lemon or an ice green with yellow to me. The insulator is in very near mint condition with a micro flake off the upper wire ridge and a few off the outside base edge. An interesting Canadian piece.