I was supposed to meet my daughter and granddaughter this morning as we were planning to take in a clay festival that had a section for kids to play with some raw clay. It was a great chance for my granddaughter to make a treasure that her mom would keep forever. I was running early and they were running a little late because their alarm clock forgot to go off. Instead of waiting or walking around the festival by myself, I decided to slip off to a nearby antique mall. Boy, was I surprised to see this old dude sitting on a shelf with a group of common insulators. There was a purple WT CD 154 with a $19.99 price tag, but most everything else, including this little guy, was priced at $6.99. (Why do they do these odd prices?) Anyway, needless to say, this insulator left the mall with me. As Daniel Ling would say in his Pittsburgh dialect, it "needs cleaned", but other than a few dings and a tiny flake off the bottom, it is in great shape. S:I is embossed on the flat round area on the top. I have seen numbers and letters before, but not this marking. The insulator appears to be aqua, maybe blue aqua. The soot gives it a green tint.