CD 121 AM . TEL & Tel. Co. In Light Blue with very Bold embossing . In Great shape, this insulator is double numbered, on the dome . In the center is a backwards 6 or 9 and then off to the side is a hand drawn 6, Add this 1 to your collection for $10 plus $5 for shipping . in pic 1 you are bidding on the 1 on the right PayPal or Money order . I have been corrected that this is most likely not a Denver mold, still a cool piece with double stamped # .