Explanatory notes
… for illuminating or other purposes (incandescent or vapour discharge lamps, X-ray tubes, radio valves, cathode-ray … may be frosted, coloured, opal, metallised, coated with fluorescent material, etc. Glass parts of envelopes … into shape for advertising signs. (C) Tubes lined with a fluorescent substance (e.g., zinc silicate, cadmium borate, …