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 09 Parts suitable for use solely or principally with the engines of heading 84.07 or 84.08. Commodity Code Description 84 09 10 For aircraft engines 84 09 91 Suitable for use solely or principally with spark-ignition internal combustion piston 84 09 99 Other