Manufacture of jewellery of gold, silver and other precious or base metal metal clad with precious metals or precious or semi-precious stones, or of combinations of precious metal and precious or semi-precious stones or of other materials
Manufacture of associated nitrogen products (nitric and sulphonitric acids, ammonia, ammonium chloride, ammonium carbonate, nitrites and nitrates of potassium)
Manufacture of electric power distribution transformers, arc-welding transformers, fluorescent ballasts, transmission and distribution voltage regulators