Here is a CHICAGO INSULATING CO. (PATd. version) embossing index [030] plain skirt (no dot), solid fizzy bubbles give this fantastic insulator a heavy milky apperance though there is almost no milky influence. This one is the rarest type of Chicago diamond groove and only several are known in this thick of fizzy bubbles. Due to it being an exceptional insulator it represented CD 135 insulators in the CD Roundup display at the 2008 Portland National.