Explanatory notes
… other fused silica 7017.20 - Of other glass having a linear coefficient of expansion not exceeding 5 x 10 -6 per Kelvin … (research, pharmaceutical, industrial, etc.), including special bottles (gas washing, reagent, Woulf’s, etc.), … (with stop-cock, bulb-shaped funnels, etc.), cylinders, crucibles, filter crucibles, special flasks (conical, …