I purchased the two outside insulators from a dealer at the Washington Courthouse Flea Market back in 1974 or 75. He had a box of glass shards and broken insulators found at the Brookfield Old Bridge factory site in NJ. At the time of purchase the pinholes were filled with a grey sandy clay and the outside very muddy. Once cleaned up you could see that the pieces were somewhat deformed. The cracks indicate that they may not have been run thru the annealing lehr properly. Both pieces are 3½" tall and dwarf the piece in the center. I wish now that I had bought more of the shards and broken pieces to do more research. NOTE: The center piece did not come from the dump site.