Here is a Whitall Tatum CD 154 in dark purple. I have been collecting for some time and this is the darkest purple I have encountered in a WT CD 154. Are there darker examples? I have seen pictures of darker units(as dark as a purple CAN PAC CD 143) but I do not know if they are genuine. All of the WT CD 154 insulators I will present have shop numbers under or to the side the MADE IN THE U.S.A. embossing and are of the same mold style. The price guide lists a dark purple WT CD 154 with no shop number under or to the side the rear embossing. Perhaps this is the piece that is really dark purple? The search continues.