Thermionic — HTS 8540
Thermionic, cold cathode or photocathode tubes (for example, vacuum or vapor or gas filled tubes, mercury arc rectifying tubes, cathode-ray tubes, television camera tubes); parts thereof
Chapter 85 › Heading 8540
2026 HTS Rev 19 Synced Rules verified Operational
Written to help non-specialists understand this page. Rates, dates, and legal facts come from the official records above and on the linked source.
HTS heading 8540 is a broad product category for certain electronic tubes that operate with thermionic, cold-cathode, or photocathode technology. It can include vacuum, vapor-filled, or gas-filled tubes, mercury-arc rectifier tubes, cathode-ray tubes, television camera tubes, and parts made for those tubes. The heading describes the general product family, not the final tariff classification.
To reach the correct 8-digit HTS code, first identify exactly what the item is and what it does, then follow the heading’s subheadings and statistical subdivisions. The narrower code may distinguish the tube’s technology, construction, intended function, or whether it is a complete tube or a part. Do not assume that a product belongs in 8540 merely because it contains a vacuum or is used in electronics; the tariff description and applicable classification rules control.
What to check
- Confirm whether the shipment contains a complete tube or a dedicated part, and describe the part’s specific function.
- Identify the tube type: thermionic, cold cathode, photocathode, cathode-ray, camera, rectifier, or another listed type.
- Check technical specifications such as vacuum or gas filling, electrode design, operating purpose, and whether the item is a replacement component.
- Read every subheading and statistical suffix under heading 8540; select the description that matches the product itself, not just its marketing name.
- Compare the manufacturer’s datasheet, commercial invoice, and product photos with the HTS wording; seek a customs broker or binding classification ruling if the alternatives remain unclear.
HTS heading 8540 summary
Thermionic is a 4-digit product category containing 2 published product-code lines in this snapshot. A heading does not carry one universal duty rate; classification must be narrowed to the line matching the product facts.
How to find your code in this category
A heading is a product category. To get the exact duty, narrow from this 4-digit heading to a sub-category (usually by material), then open the 8-digit code that matches your product.
Open any code in the tables below to see its exact duty rate, a duty calculator (enter your shipment value → estimated duty and landed cost), the rate-change history chart, and the country-by-country breakdown (including Section 301/232 add-on duties).
Why you have to click in: a single category can contain products with very different duties. The rate depends on the specific product — its material and construction — and on the country of origin, and those only get pinned down at the 8-digit code level. That is why this page points you to codes instead of showing one rate for the whole category.
Sub-categories
| Code | Description |
|---|---|
| 8540.11 | Color |
| 8540.12 | Monochrome |
| 8540.20 | Television camera tubes; image converters and intensifiers; other photocathode tubes |
Product codes & duty rates
👇 Each row is a specific product code — click a blue code to open its full page with exact duty rates by country, the rate-history chart, and a duty calculator. 👉
| Code | Description | General (MFN) | Special | Column 2 |
|---|---|---|---|---|
| 8540.40.10 👉 | Data/graphic display tubes, monochrome; data/graphic display tubes, color, with a phosphor dot screen pitch smaller than 0.4 mm | 3% | Free | 35% |
| 8540.60.00 👉 | Other cathode-ray tubes | 3% | Free | 35% |
"Special" shows the free-trade-agreement rate; open a code to see exactly which countries qualify.
Common questions
What products fall under HTS heading 8540?
Thermionic, cold cathode or photocathode tubes (for example, vacuum or vapor or gas filled tubes, mercury arc rectifying tubes, cathode-ray tubes, television camera tubes); parts thereof. To classify a specific item you must pick the matching sub-category and 8-digit code above; the right choice usually depends on the material and construction of the product.
How do I choose the right code within this category?
Start from the sub-categories (typically divided by material—for example cotton versus man-made fibers), then open the active 8- or 10-digit code that matches the product. When unsure, a licensed customs broker or a CBP binding ruling can confirm the classification.
Reference information only, not customs, legal, or classification advice. Confirm the current code and rate against the official HTS before you import.