A small (80 mm / 3.125 inch) diameter porcelain insulator from Russia, incused with the letters TMK., inside of a circle. This is the same size and similar shape to various CD 472 "N80" insulators. This matches up closest to either U-2254 or U-2257. This one just arrived, so here is a new side view photo, showing the marking. Actual color is "oatmeal" white, under all that soot. The surface has lots of little "zits" (rough spots) and brown "freckles" baked into the glaze. After a couple of days soaking in Oxalic acid and some mild scrubbing, it is looking a lot better.

This insulator may possibly be of German origin, but it was found on Russian soil.