231911 Glass in the mass, in balls (except microspheres), rods or tubes, unworked

23191110 Glass in the mass (excluding glass in the form of powder, granules or flakes) 23191130 Unworked glass in balls or rods (excluding glass balls as toys, glass balls which have been ground after shaping, used as stoppers for bottles, glass microspheres <= 1 mm in diameter) 23191150 Unworked glass tubes (including tubes which have had fluorescent material added to them in the mass) (excluding tubes coated inside with fluorescent material)