I picked these up from a Craigslist add in Pittsburgh about 10 days ago. Seller is a metal scraper who was tasked to pull wire out of a steel mill. The insulators and wire were still connected and with no set disposition for the insulators, he decided to sell them on CL. Seller said there were no other insulators available...just the 162's and 257's. According to the seller, the steel mill was/is called MRI Steel. I could find no information about MRI Steel on Google, so I can't provide a history about the mill or where these came from. I asked about getting photos of them still up in the air or perhaps a photo of the inside of the mill or the exterior...I thought it would be a nice go-with for the story...but the seller was unresponsive. So that's it for this particular adventure. Cleaning them up now and if I find anything unusual, I'll post a picture.