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 04 STEAM OR OTHER VAPOUR POWER UNITS. 84 04 90 PARTS: AUXILIARY PLANT FOR USE WITH BOILERS OF HD. 84.02 OR 84.03 Commodity Code Description 84 04 90 00 PARTS: AUXILIARY PLANT FOR USE WITH BOILERS OF HD. 84.02 OR 84.03