Section 16 Machinery and mechanical appliances; electrical equipment; parts thereof; sound recorders and reproducers, television image and sound recorders and reproducers and parts and accessories of such articles 84 Nuclear reactors, boilers, machinery and mechanical appliances; parts thereof 84 21 Centrifuges; filtering/purifying machinery... for liquids or gases 84 21 39 Machinery and apparatus for filtering or purifying gases, nes 84 21 39 00 Machinery and apparatus for filtering or purifying gases, nes Commodity Code Description 84 21 39 00 00 Machinery and apparatus for filtering or purifying gases, nes