Chapter 85 — Electrical machinery and equipment and parts thereof; sound recorders and reproducers, television image and sound recorders and reproducers, and parts and accessories of such articles

Heading 8540 — Thermionic, cold cathode or photocathode valves and tubes (for example, vacuum or vapour or gas filled valves and tubes, mercury arc rectifying valves and tubes, cathode ray tubes, television camera tubes).

National subdivision 8540.7 — Microwave tubes (for example, magnetrons, klystrons, travelling wave tubes, carcinotrons), excluding gridcontrolled tubes: