I recently came across a lot of insulators made by this modern compay, Allied Bolt And Screw Corporation. I've been trying to find some marked insulators made by them and lucked out a few months ago. Here is a picture of some telephone drop wire insulators that are marked by them. There was also two split screw eyes but they were not marked. Allied Bolt has been in buissness before the 1940's and supplied bolts, screws etc to the war effort and other. Still in production today supplying pole line hardware across the globe. What's neat are these spools are beefier than the older styles made by past companies. I have yet to get a nylon wire holder insulator by them that has a hex head on it to tighten with a wrech or socket. Time and search will tell.