I found this small rubber insulator back in January of 2005, along the Long Island Rail Road tracks (L.I.R.R.). There are no markings on it, of any kind. It is very worn out and looks very old. It is much shorter and narrower than a typical glass insulator. Can anyone tell me how old this insulator is and who may have produced it ? Thank you.

Update: These were replacement insulators that were used after a glass insulator broke. I believe they were used in the early-to-mid-1900's.