Continental made 5 different marked styles for replacements on telegraph poles. R-1, R-3, R-4, R-5 and the mid span transposition spool RC-1. There are two other that might be Continental products I have in other pictures. The R-1 and 3 were designed to go over the metal pin when the wooden cob had broken or rotted off. The R-4 was to go on regular wooden pins and the R-5 to replace carrier circut insulators. The RC-1 replaced mid span CD 1049 glass spools. Here is a picture showing the pins with the insulators.