A large Pyrex-looking borosilicate glass ribbed "thing" that looks like a bushing. Yellow-straw glass, has 3 base threads to screw it into position, a black rubber gasket and the base is recessed. Has a large 1" and shallow dome top clam shell chip to the lip edge edge, another 5/8" dome top chip to the lip edge, a single match head micro flake to the dome top lip edge, and a 5/8" lowest rib lip edge chip. Has a corrugated base. 4 1/4" inches tall X 2 1/2" wide at the top lip edge to edge. Solid glass except for the recessed base and very heavy. I have no idea what this is or was used for. Update: Perhaps some sort of light cover. This weighs 1.6 pounds alone. Many more pictures available. Asking $75 PP in the USA. Now asking $59 PP in the USA.