This insulator is a CD 253 embossed on the front; Knowles Cable Insulator with no patent date. It is the [010] listing in the book. The insulator is a green color with some light amber swirling in the glass. It is in very near mint condition with only a small narrow scrape mark on the front left hand ear, a tiny 1/8" peck mark on the back ear point, and a tiny peck mark on the lower right hand ear edge. This is a really beautiful color shade in this insulator. Priced at $195.00 plus shipping.