HS Code 85.40 – Thermionic, cold cathode or photo-cathode valves and tubes (e.g. vacuum, vapour, gas filled valves and tubes, mercury arc rectifying valves and tubes, cathode-ray and television camera tubes)

HS code 8540 is a 4-digit heading in the Harmonized System that covers: Thermionic, cold cathode or photo-cathode valves and tubes (e.g. vacuum, vapour, gas filled valves and tubes, mercury arc rectifying valves and tubes, cathode-ray and television camera tubes). Heading 8540 encompasses thermionic, cold cathode, or photo-cathode valves and tubes, representing a foundational era of electronics before the widespread adoption of semiconductors. This diverse category includes vacuum tubes, gas-filled tubes, mercury arc rectifying valves, cathode-ray tubes (CRTs), and television camera tubes. While many applications have been supplanted by solid-state devices, these tubes remain critical for niche, high-performance, or legacy systems. The scope covers the tubes themselves, not the apparatus they are incorporated into. Key sub-categories include display tubes (like CRTs for monitors or oscilloscopes), power tubes (for high-frequency or high-power applications such as magnetrons in microwave ovens or klystrons in radar), and specialized tubes for scientific instruments (e.g., photomultiplier tubes, X-ray tubes). For trade compliance, understanding the specific type and application of the tube is vital, as safety standards (especially for X-ray tubes) and export controls can apply. Historically, this heading was central to the electronics industry, powering early radios, televisions, and computers. Today, its significance lies in specific industrial, medical, and audio/military applications where their unique characteristics (e.g., high power, radiation resistance, specific frequency ranges) are still indispensable. It forms a distinct classification within Section XVI, separating these vacuum/gas-filled devices from the semiconductor devices of subsequent headings.

Cathode Ray Tubes (CRTs), X-ray tubes (for medical/industrial use), Magnetrons (for microwave ovens/industrial heating), Klystrons, Traveling Wave Tubes (TWTs), Vacuum tubes (for audio amplifiers/industrial controls), Photo-multiplier tubes, Geiger-Müller tubes, Mercury arc rectifying valves, Thyratrons, Neon indicator tubes, Glow discharge tubes, Television camera tubes, Image intensifier tubes, Display CRTs (for specific industrial monitors), Industrial X-ray tubes (for non-destructive testing), Rectifier vacuum tubes, Amplifier vacuum tubes, Electron beam guns, Backward Wave Oscillators (BWOs), Plasma display panels (early types), Spark gaps, Ignitrons.

Misclassification often occurs when these tubes are part of a larger apparatus. For instance, an X-ray *tube* belongs to 8540, but a complete X-ray *apparatus* for medical purposes falls under 9022. Similarly, a CRT is 8540, but a finished television or computer monitor containing a CRT would be 8528. Traders might also confuse these with semiconductor devices (8541) or electronic integrated circuits (8542), which are fundamentally different solid-state technologies. The key is to classify the tube itself as a component, not the end-use product it enables. The 'valves and tubes' aspect is the defining characteristic.

In 2025, the top exporters of HS code 8540 in UN Comtrade data were the United States ($474M, 22% of world exports), France ($323M) and the Netherlands ($315M). World exports came to about $2.1B, 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.

In 2025, the top importers of HS code 8540 in UN Comtrade data were the United States ($250M, 12% of world imports), Greece ($214M) and China ($154M). World imports came to about $2.0B, 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.

HS code 8540 is a 4-digit heading under Chapter 85 of the Harmonized System. The first 2 digits (85) identify the chapter, and digits 3-4 (40) specify the heading. This code contains multiple 6-digit subheadings for precise product classification.