Most CD 288 insulators embossed with the R.D. Mershon name only have a single ridge on the umbrella. But a much smaller number are found with three such ridges, such as the one shown above. The scarcity of the units, along with their apparent affiliation to insulator manufacturers in Denver, have resulted in "triple ridge" Mershon insulators being the symbol and namesake of Colorado's Triple Ridge Insulator Club. For more information on Mershon insulators, read this month's article on insulators manufactured by Robert Good, Jr. beginning on page 27 of this issue.