I bought this M-3060 Fred Locke a few years back... thanks Elton. These 3 part insulator were used in Ontario Canada around 1904-5 and supplied power to copper cliff in the town of Sudbury. This insulator has a nicer glaze with green undertones and is stamped with a letter "?" Not to sure. I am adding an original pin I found on the trail to the set. It has very nice embossing reading P&B Chicago. For what I have into it originally plus the pin and shipping I'm asking $200