A couple years back I posted three spools which I thought were German fence insulators. Though they could have been used that way, these are, you guessed it, thread guides. After doing some research on the internet, the closest thing I could come to the embossing meaning was a company from the U.S. I determined the pieces were made at the time for this company in Germany. The spools are marked M.B. Co. which I believe is Mitchell-Bissell Co. located in North Carolina. They started in 1894 providing guides and assemblies for the industrial sewing industry. They are still in buisness today. The spools are marked M.B. Co. 4 79B/Germany, 1 1/16"D X 3/4"H, M.B. Co. 87 3/8", 1 1/4"D X 5/8"H, M.B. Co. 87 3/8"/Germany 1 5/16"D X 5/8"H. The screw guide is marked M.B. & Co./218. It measures1 5/16"H X 5/8"D X 2 1/2"L counting screw. Could not find any other info out on there website but they have similar products in plastic, ceramic, and metal. The third picture shows the markings on the spools.