This is a strain made by Ohio Brass for use on trolley cables to insulate the conductor wires from the cables holding them up. They were wood strains with metal caps on each end. They were 11 1/2" long and 2" wide at the widest point on the metal caps. I actually have two different types. One is shown and the other has a double ring at one end and is embossed with a circled "B" at one end and a circled "W" at the other end. Thanks to Rick Soller for this info.