This massive Ohio Brass multipart was used as a base insulator for a two part stacked pin type arrangement on one of the lines that once used the M-3890 in upstste new york .The steel cap has a threaded hole where a standard pin can be screwed in so that an M-4395 Ohio Brass cross top can be installed on top . The eyelets in the cap were so that strings of suspensions could be double dead ended with the top insulator being used to hold the jumper loop. These insulators were mostly used as regular pin types and not as a double dead end insulator base. I have only found shards these on one 15 mile stretch of line. These were used only on the" B "phase (the ridge top conductor ) wile the lower lines on the cross arm of the pole structure had stacks of two Ohio Brass M-4395's.[id=260298944] This is the only savable insulator like this I I found . The line crews seem to have been into smashing the insulators and scraping the steel caps ... Fortunately, this one got missed! I have seen no evidence of these being used any place else. The top skirt is 17" wide and it ways at least 75 pounds . It has standard 2" threads. the insulator would have been used in an arrangement like this [id=257544603] these insulators remained in service from about the early 1920's to the 1930's when the line was dismantled. please see the next two photos for pictures of the cap and underside of this insulator