These two unique pieces were made by Line Material Co. The first one has a patent US 1,858,045 5/10/1932 for special clamp design. It was made for a two wire line that goes down through the clamp. The second piece is ink marked F/ LM symbol DE2MI and 211370X on the metal pipe clamp bracket. It also is a special wire design. I haven't found a patent for this one yet.