Todos os tubos C 18 7304.10 7304.10 C 19 7304.20 7304.20 c 20 7304.31 7304.31 c 21A 7304.39 7304.39 c 21B 7304.90 7304.90 c 22A 7305.11 7305.11 c 22B 7305.12 7305.12 c 7305.19 7305.19 c li 7305.20 7305.20