In this picture the "standard" CD 127 is compared versus the "knob" variation CD 127 embossed "W.U.T. Co. / Cauvets Pat / W. Brookfield" embossed on the front dome and "Feb 22 - 70 / No 55 Fulton St N.Y." on the back dome. This is what I will call the "knob" dome style and was found on the Central of Georgia Railway telegraph line. I have found several different size embossings so have concluded that this was a design change and not a single error mould.