These two pieces were made for the Canadian Line Material Co. The white one is ink marked F/LM symbol and 3750-D.G. catalog number. The second is a earlier piece just marked with a triangle in a circle. These are definatly heavy duty pieces., I would love to find a CLM catalog or a Canadian Ohio Brass Co. catalog for that matter. It is hard enough to find catalogs for U.S. manufacturers but even harder for foreign countries. Thanks to all those foreign insulator collectors who post and provide info. We all greatly appreciate it.