… example, vacuum or vapour or gas filled valves and tubes, mercury arc rectifying valves and tubes, cathode-ray tubes, …
Explanatory notes
… example, vacuum or vapour or gas filled valves and tubes, mercury arc rectifying valves and tubes, cathode-ray tubes, … (for example, magnetrons, klystrons, travelling wave tubes, carcinotrons), excluding grid-controlled tubes : 8540.71 - - … and may incorporate means of cooling (cooling fins, water circulation system, etc.). There are many kinds of valves …