Sheets of optical glass, drawn or blown, but not otherwise worked (excl. glass coloured throughout the mass "body tinted" opacified, flashed or having an absorbent, reflecting or nonreflecting layer)
Sheets of glass, drawn or blown, otherwise unworked (other than coloured throughout the mass "body tinted", opacified, flashed or having an absorbent, reflecting or nonreflecting layer, optical glass)