This insualtor is a CD 164 embossed on the front McLaughlin and No - 20 on the back. This is the  listing in the book. It is a beautiful light blue color. The insulator is in near mint condition with only a 1/8" flake off the back base. A nice blue McLaughlin that is almost a light cornflower blue color. $15.00 plus shipping cost. Payment by PayPal friends or gift mode or check. More photos available on request.