Tough to describe these but they were recovered near an overhead crane in St. Louis, MO in an 1890 structure built to manufacture war material. It was described to me that the flat arm held a DC wore as the crane moved up and down and were mounted to a wood support with square headed lag screws.

This sale includes the two insulators shown and two sets of lag screws. In as found condition with paint. Both have some corner chipping and one appears to have a wire rub on the bottom of the arm. Both are unmarked and measure 2" x 5" x 4.5" deep.

I'm asking $35 plus shipping for this set.