CD 133, embossed Patent Dec 19 1871 on the crown side. An outstanding two-toned example! It appears this insulator was partially sheltered from the sun and received direct exposure from one side only. The exposed side turned a rich purple shade, while the opposite side remained a lighter sun colored amethyst. Possibly used on a bracket under an eave? Some high point wear and several flat base flakes, but all of this goes mostly unnoticed when this beauty is sitting proudly on your shelf. A top-shelf item, possibly unique. $2,750, plus actual shipping/optional insurance.