Awards Central/Southern Counties Insulator Club Award, Best Exhibit using Southern California Insulators Nor-Cal Insulator Club Award, Best Exhibit using Western Insulators The most common shape and the industry standard for railroads, the Bell System and Western Union telegraph after its introduction in 1922 is the CD 154. Over a dozen different companies in north America manufactured this style. Manufacturers of insulators in Spain, Australia, Chili, Argentina, Nicaragua, Brazil and Colombia produced copies of this popular shape. A beautiful assortment of 48 examples show a wide variety of color.