Here are three different colors of the tough CD 505 insulators. These are attributed to Iran and the Mehr family -- The marking is Farsi for Mehr -- the story of these in in crown jewels: https://www.cjow.com/archive/article.php?month=12&a=12Foreign%20Insulators.htm&year=1979

Actual postage additional

Left is a nice shade - crude but VNM -- $50

middle is more of an aqua -- small bruise inside skirt -- $40 (Sold)

Right is more green with just a tiny base flake -- $45 (Sold)