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, including centrifugal dryers; filtering or purifying machinery and apparatus, for liquids or gases. 84 21 21 For filtering or purifying water. 84 21 21 00 For filtering or purifying water. Commodity Code Description 84 21 21 00 000 For filtering or purifying water.