8540: Thermionic and cold cathode valves and tubes

854011: Colour cathode-ray television picture tubes, monitors 854012: Monochrome cathode-ray picture tubes, monitors 854020: Television camera tubes and other photo-cathode tubes 854030: Cathode-ray tubes, except for television 854041: Magnetron tubes 854042: Klystron tubes 854049: Microwave tubes, except magnetron/klystron 854081: Receiver or amplifier valves and tubes 854089: Electronic valves/tubes, except receiver/amplifier 854091: Parts of cathode-ray tubes 854099: Parts of electronic valve & tubes, except cathode ray 8540: Thermionic and cold cathode valves and tubes