Explanatory notes
… by weight more than 50 % of alumina (Al 2 O 3 ) or of a mixture or compound of alumina and of silica (SiO 2 ) … products of heading 69.02 , are in many cases not permanent fixtures, such as retorts, reaction vessels, crucibles, … or pipe fittings, even if intended for use as permanent fixtures in construction work. The heading does not , …