Here are some more Colonial Insulator Company marked pieces. The first is a spool with the C I in a circle marking on to and a M I marking on the front lower edge (unknown), second is a wire holder made for Line Material Co with the C I marking and LM's marking beside it, Third is a wire holder made by them for National Metal moulding Co. with NAT"L on the front and the C I marking on the back. Next is another Line Material wire holder with an L on the front and LM's marking plus 3800p (catalog number) on the back. Don't know if related or meaning of the L. Next up is a Line Material with just the triangle and LM and a squiggly line beside it on the back is A-1569 (unknown cat number). Last is a cleat with C.S.I.Co. (Colonial ISign and Insulator Co.). Elton Gish has a spool and cleats pictured on his wonderful website and a great wealth of info avalible too. The bottom shows another National wire holder so you can see the C I marking on the back, Next is a very unique cable holder with a bolt hole going down the one side, solid porcelain, it is marked diamond L and A-43 on the back, Next is another unique spool marked diamond L and A-33 on the fron C I on the side. On eBay someone had a smaller version for auction but I was outbid. It was marked A-34. Last is a C I marked spool. I would love to solve this mystery on these unique insulators. Colonial Insulator company was a job shop making insulators with just there marking and for numerous other companies. Square D, Illinois, Universal Clay Products, and Porcelain Products Inc.and Knox Porcelain Corp. all made insulators for other companies besides there own products.