Here are some photos of my collection of forestry insulators and similar. Some are solid pieces that were tie wired to a tree and the wire run through them and others were split pieces that could be put on after the wire was run or to replace an broken insulator. This picture is of all Thomas pieces. The donut type were either recessed embossed Thomas or embossed Thomas Made In U.S.A., One octogonal piece is marked Thomas No.22. One round piece is marked with a recessed T.