Click on a Primary Embossing in the left pane to view  the corresponding Style Number to CD Number chart in this pane. Most newer insulators have style numbers embossed on them but some insulators (new or old) do not have style numbers!

The style number is generally located in one of two places:

1. After the Primary Embossing and preceded by a dash, such as "HEMINGRAY-42"
   
   
2. After the word N^o, such as "WHITALL TATUM CO. N^o 1"

Numbers on the dome of the insulator are not considered style numbers. Some style numbers are alphabetic, such as "TW",  or alphanumeric such as "D-510".

Style Number information from The Glass Insulator in America; 1988 Report with updates from the author. Used with permission.