These three strains are Westinghouse made. The first one is marked with Pat. 9-22-14. The second is a later desisign with Pat. Sept 25 1914 (in an arc) on top and the Westinghouse logo on the bottom. I could not find a patent for this strain with that date either but did find one showing the first piece for a connector. It was US1794934A by Niles A Wahlberg Wilkinsburg, Pa. granted March 3, 1931. The last piece is just marked with the catalog number 504.