This is a CD166 smooth bottom (SB), California insulator. The embossing index is  and the F-skirt reads A011 above California. The R-skirt has nothing, but it does have a bunch of imprints on it from the manufacture's cooling process. It also has a few chips but no wire marks. The unique and rare quality about this insulator is the color! It is RARE smoky green color, and has small air bubbles and particals inside the glass. This insulator comes directly off a power pole in Southern California set in 1954. The color can also be passed for a purple sage two tone. You can look up the price and see that it's worth $150-$250 mint, but I'm starting the bidding low so have fun! And thanks for looking!Buyer will pay for the shipping , from California, and insurance is optional. I am not responsible for damage during shipping, I am very professional with my selling and will not ship you damaged goods. If you have any questions feel free to write me an email. Any problems I will always try to work out.