Explanatory notes
… monocles, etc., used for correcting vision, generally have optically worked lenses. Protective spectacles and … or tinted), of safety glass, of plastics (poly(methyl methacrylate) polystyrene, etc.), of mica, or of metal (wire … 90.01 if optically worked; eyepieces of materials other than glass are classified in heading 90.01 if they …