Product classification
HS code for Traveling wave tube: 8540.79
Tubes, microwave (for example klystrons, travelling wave tubes, carlinotrons), excluding magnetrons and grid-controlled tubes.
Classification of traveling wave tube under HS 8540.79
The traveling wave tube (TWT) is classified under HS code 8540.79. This classification falls within Chapter 85, which covers electrical machinery and equipment and parts thereof. Heading 8540 specifically addresses thermionic, cold cathode, or photo-cathode valves and tubes, such as vacuum or gas-filled tubes. The TWT is a specialized vacuum tube used in electronics to amplify radio frequency (RF) signals in the microwave range. Because it operates on the principle of interaction between an electron beam and a slow-wave structure, it is categorized as a microwave tube. While magnetrons (8540.71) and klystrons (often 8540.72) are also microwave tubes, 8540.79 serves as the specific designation for "other" microwave tubes, including traveling wave tubes and carcinotrons. The classification is based on the functional microwave amplification properties and the physical construction as a vacuum-sealed electronic component. These devices are critical in satellite communications, radar systems, and space-based transmitters where high-power microwave amplification is required.
- Covers
- Helix traveling wave tubes
- Coupled-cavity TWTs
- Microwave amplifiers for satellite communications
- Broadband TWTs for electronic warfare
- Pulsed traveling wave tubes for radar
- Also under 8540.79
- L3Harris TWT (satellite communication)
- CPI Klystron (particle accelerator)
- Thales TWT (radar system)
- Varian Klystron (medical linear accelerator)
- Teledyne TWT (electronic warfare)
Codes often confused with 8540.79
Common mistake. Traveling wave tubes are often misclassified under HS code 8540.71, which is strictly for magnetrons. While both are microwave tubes, their internal mechanisms differ significantly. Another common error is attempting to classify them under HS code 8541, which covers semiconductor devices like transistors. TWTs are vacuum-based thermionic tubes and must remain in 8540, even if they perform similar amplification functions to solid-state microwave power amplifiers (SSMPAs).
Top exporters and importers of HS 854079 (the code used for traveling wave tube), 2025
In 2025, the largest exporter of HS 854079 (the code used for traveling wave tube) in UN Comtrade data was France, with 28% of world exports; the largest importer in UN Comtrade data was the United States, with 23% of world imports. Countries that did not report 2025 data are estimated from partner records, which can understate them.
Figures cover everything classified under HS 854079, not only traveling wave tube.
Top exporters 2025 · share of world exports
- 1 France $98M 28% of world exports
- 2 United States $88M 25% of world exports
- 3 Germany $72M 20% of world exports
World total: $354M Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 United States $66M 23% of world imports
- 2 Japan $44M 15% of world imports
- 3 Canada $27M 9.5% of world imports
World total: $286M Reported figures on UN Comtrade ↗
How these figures are built
109 countries reported 2025 trade to UN Comtrade in HS 2022, and their own totals are used. Countries that did not report are estimated from what other countries recorded trading with them. Those estimates miss trade with other non-reporting countries, so they can be low, and a non-reporting country can rank higher than shown or be missing from the list. World totals add both and leave out trade between two non-reporting countries. Figures are in current US dollars; reported imports are mostly valued CIF and exports FOB, and exports include re-exports. The UN Comtrade links show the underlying records; they can also list a few reporters left out here (regional groups and older HS editions).
Source: UN Comtrade (United Nations Statistics Division), 2025 annual data.
Brazil NCM code for traveling wave tube
Brazil classifies traveling wave tube under NCM 8540.79.00: HS 8540.79 with 00 added.
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about traveling wave tube
What is the HS code for Traveling wave tube?
The HS code for Traveling wave tube is 854079 (Tubes; microwave (for example klystrons, travelling wave tubes, carlinotrons), excluding magnetrons and grid-controlled tubes). The specific HS code for a traveling wave tube is 8540.79.
How do I classify Traveling wave tube for customs?
Traveling wave tube is classified under HS code 854079 — Tubes; microwave (for example klystrons, travelling wave tubes, carlinotrons), excluding magnetrons and grid-controlled tubes. This is a 6-digit subheading level code.
Are solid-state microwave amplifiers classified here?
No, solid-state amplifiers are semiconductor-based and are typically classified under heading 8541 or as part of a specific assembly in 8543.
Which countries are the top exporters of traveling wave tube (HS 854079)?
In 2025, the top exporters of HS 854079 (the code used for traveling wave tube) in UN Comtrade data were France ($98M, 28% of world exports), the United States ($88M) and Germany ($72M). World exports came to about $354M, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Which countries are the top importers of traveling wave tube (HS 854079)?
In 2025, the top importers of HS 854079 (the code used for traveling wave tube) in UN Comtrade data were the United States ($66M, 23% of world imports), Japan ($44M) and Canada ($27M). World imports came to about $286M, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Is the HS code for Traveling wave tube the same in all countries?
The base HS code 854079 for Traveling wave tube is internationally standardized for the first 6 digits across 200+ countries. Individual countries may add additional digits for national tariff lines and specific classifications.
What is the NCM code for traveling wave tube in Brazil?
In Brazil, traveling wave tube (HS 854079) is classified under NCM 8540.79.00.