I found this insulator at the base of a power pole from a power line that ran through the woods, right alongside a railroad's R.O.W. (found on January 10th, 2008). The line ran for exactly 1 mile. I checked each end of this line and both ends were cut and had no power going to them anymore. I then walked the entire mile and did a quick investigation of each pole. Some poles had fallen down, but their crossarms were still suspended in the air by vines and tree branches. Other poles had started to fall, but are being held up by the trees. One pole had a wire running to the next pole with a tree in the middle. The tree had been leaning on the wire for so long, that the tree grew completely around it and swallowed it up. This line has been abandoned for a very long time. The poles look pretty old. Most of the insulators that are still up on the crossarms are the exact type that I have pictured here. This one had gotten knocked off the pin by a fallen tree and it landed at the base of the pole. The inner skirt is partially missing as you can see from this photograph but other than that, it is perfect. There are no markings of any kind, anywhere on this insuator. I don't know which company made this piece. I also do not know how old it is and I do not know the "M" number of it either, nor do I know how much it is worth. I took 4 photographs of it and combined the 4 together into 1 image. Enjoy !!! UPDATE: It is an M-2611A, made by Ohio Brass. This style was only produced between 1916 - 1924. I have 4 of these now.