Source-backed base HTS8540.99.40.00

HTS 8540.99.40.00 Duty Rate: Free

Name: HTS 8540.99.40.00 Electron guns; radio frequency (RF) interaction structures for mi... US import duty 2026
Creator: TariffsChart
License: https://tariffschart.com/data-license

Description: Electron guns; radio frequency (RF) interaction structures for microwave tubes of subheadings 8540.71 through 8540.79, inclusive

Verified source

Base HTS fields include an official source, retrieval date, and calculation trace. This page still remains a planning and broker-review prep page.

US import duty quick answer

HTS 8540.99.40.00 (Electron guns; radio frequency (RF) interaction structures for mi...) has a source-backed MFN base duty of Free. This is not a final filing rate: unresolved policy layers are neither treated as zero nor added into a guessed total.

HTS code

8540.99.40.00

Base MFN rate

Free

Planning view

Known subtotal: base Free; final rate unresolved

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China-origin duty stack

MFN base duty

Free

This is only the USITC HTS general-rate field. It does not include Chapter 99 or trade-remedy layers.

Section 301 / Chapter 99

Review required

Do not hard-code 7.5% or 25% from a product category or historical list. Bind the rule directly to USTR/HTS Chapter 99 sources, origin, effective dates, and exclusions.

Section 122 historical layer

Expired historical window

Do not add the expired temporary layer to a current shipment. Review it only for an applicable historical entry date against official sources.

Section 232 / product-specific remedies

Product review

Steel, aluminum, copper, autos, semiconductors, lumber, and derivatives require current annex, origin, content, and Chapter 99 review.

AD/CVD scope

Manual scope review

An HTS match is only a risk signal; the written scope of the order controls legal coverage.

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Get an email when an official-source fingerprint changes, with retrieval context and a review item in your workspace. A signal is not a legal determination.

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What is this HS code?

HTS 8540.99.40.00 corresponds to “Electron guns; radio frequency (RF) interaction structures for microwave tubes of subheadings 8540.71 through 8540.79, inclusive.” Final classification still depends on material, use, specifications, and statistical suffix.

Description

Electron guns; radio frequency (RF) interaction structures for microwave tubes of subheadings 8540.71 through 8540.79, inclusive

Data source and update date

Base source: USITC HTS revision feed, retrieved 2026-09-07. Additional-layer rates are not currently published.

How the duty stack works

1Confirm the full 8- or 10-digit HTS code.
2Read the source-backed MFN base duty.
3Resolve Chapter 99 and origin policy layers by entry date.
4Check Section 232, AD/CVD, quotas, exemptions, and trade agreements.
5Publish a final total only when every applicable layer has a source chain.

Section 301 status

This page publishes the base rate only. Section 301 requires direct origin, Chapter 99, effective-date, and exclusion verification.

Duty rate by origin

The same HS code can produce very different planning outcomes by origin. This table compares scenarios; it is not a final filing determination.

Origin	MFN	Section 301	Section 122	Section 232	Planning view	Note	Compare in calculator
China	Free	Review required	Not current	Product review	No unsupported total	Check Chapter 99, exclusions, AD/CVD, quotas, and entry date.	Compare in calculator →
Vietnam	Free	Current-origin review	Not current	Product review	No unsupported total	A different origin changes the policy stack; do not reuse China rates.	Compare in calculator →
Mexico	Free	Current-origin review	Not current	USMCA and product review	No unsupported total	Confirm USMCA eligibility before product-specific measures.	Compare in calculator →

Base HTS information

This section only publishes base HTS information with source fields attached. Base HTS and additional-duty review work stay separate so the page does not overstate unsupported composite estimates.

Base MFN rateFreeExact official field

HTS general rate field: Free

Rate-output note: only the base HTS field is shown here. Additional duties, Chapter 99 treatment, exclusions, or AD/CVD still require separate review.

Calculation method

Exact official field

Source name

USITC HTS revision feed

Source URL

https://www.usitc.gov/2026_hts_revision_18

Retrieved date

2026-09-07

Effective date

Version / revision

2026-revision-18

Confidence status

official-source

Review status

Verified

Visual calculation trace

The public page separates base HTS, additional layers, and public visibility. Dashed bars show a component may exist in the planning stack but is not yet source-complete enough to publish as a public rate.

Base HTS

Exact official field

Free

Country / temporary additional-duty layer

This layer is hidden until a dated rule is directly bound to its official document, economy, HTS scope, and exclusions.

Still review-gated

Section 301 / Chapter 99 layer

This layer is hidden until a dated rule is directly bound to its official document, economy, HTS scope, and exclusions.

Still review-gated

Public-readiness signals

Base-field precision

94%

Exact official field

Source freshness

88%

Inside freshness window

Public visibility

22%

Still review-gated

Calculation trace

HTS line 8540.99.40.00 maps to the USITC general duty field "Free".
The field is a single simple ad-valorem rate, so the public base rate is Free.

Rate output disclaimer

Planning estimate only
Not a customs ruling
Not legal, tax, or customs advice
Confirm with official sources or a licensed customs broker

China → US additional-duty review

China-origin additional-duty layers do not appear here as a final public rate until every component has source metadata, dates, and review status.

Country / temporary additional-duty layer

Source chain incomplete

This layer is hidden until a dated rule is directly bound to its official document, economy, HTS scope, and exclusions.

Section 301 / Chapter 99 layer

Source chain incomplete

This layer is hidden until a dated rule is directly bound to its official document, economy, HTS scope, and exclusions.

Planning composite estimate is hidden

No composite rate is published until every policy layer has a direct source and applicability record.

China → US review checklist

Treat the following items as a broker/compliance review checklist, not as an automated determination. The core checks are Chapter 99, Section 301, USTR exclusions, AD/CVD, quotas or safeguards, and broker confirmation.

HTS code has filing-level detail to review

success

The entered code (8540.99.40.00) is specific enough to start a rate review, but classification still requires product facts and broker/official confirmation.

Open USITC HTS search

Product facts captured for ruling comparison

success

Use the product description when comparing material, construction, principal use, and classification rationale from rulings.

Search CBP CROSS

USITC HTS candidate record returned

success

Candidate 8540.99.40.00: Electron guns; radio frequency (RF) interaction structures for microwave tubes of subheadings 8540.71 through 8540.79, inclusive. General duty field: Free.

Open USITC HTS search

Simple general duty rate parsed for planning

success

TariffsChart can apply Free as a planning base duty rate. Still verify special rates, units, footnotes, and applicability.

China-origin trade-remedy and Chapter 99 check required

danger

For China-origin goods, verify Section 301 coverage, exclusions, IEEPA/other current trade-remedy FAQs, and any required Chapter 99 secondary classifications. The automated result does not determine coverage.

Open CBP Section 301 FAQ

AD/CVD scope cannot be determined from HTS alone

danger

Search ACCESS/AD-CVD by country, product, commodity, case number, and HTS. Scope language controls; an HTS match is only a screening signal.

Open AD/CVD Search

Related HTS codes

Verified HTS detail pages from the same heading or chapter. Use them to compare adjacent classifications, materials, and use cases before broker review.

Chapter 85: Electrical machinery and electronics →

8540.11.10Base rate: 15%

Non-high definition, non-projection, having a video display diagonal exceeding 35.56 cm

Source retrieved: 2026-09-07

8540.11.24.01Base rate: 7.5%

Having a video display diagonal not exceeding 34.29 cm

Source retrieved: 2026-09-07

8540.11.30.00Base rate: 15%

High definition, having a video display diagonal exceeding 35.56 cm

Source retrieved: 2026-09-07

8540.11.44.01Base rate: 7.5%

Having a video display diagonal not exceeding 34.29 cm

Source retrieved: 2026-09-07

8540.12.10.00Base rate: 3.6%

Non-high definition

Source retrieved: 2026-09-07

8540.12.20.00Base rate: 3.6%

High definition

Source retrieved: 2026-09-07

8540.12.50Base rate: 3.3%

Non-high definition

Source retrieved: 2026-09-07

8540.12.70.00Base rate: 3.3%

High definition

Source retrieved: 2026-09-07

8540.20.20Base rate: 6%

Cathode-ray tubes

Source retrieved: 2026-09-07

8540.40.10Base rate: 3%

Data/graphic display tubes, monochrome; data/graphic display tubes, color, with a phosphor dot screen pitch smaller than 0.4 mm

Source retrieved: 2026-09-07

8540.60.00Base rate: 3%

Other cathode-ray tubes

Source retrieved: 2026-09-07

8540.71.20.00Base rate: Free

Modified for use as parts of microwave ovens

Source retrieved: 2026-09-07

Official-source openings

These are the official-source entry points this route should open and preserve before relying on any shipment assumption.

USITC HTS lookup for 8540.99.40.00

official-source · 2026-09-09

Candidate HTS: 8540.99.40.00 Description: Electron guns; radio frequency (RF) interaction structures for microwave tubes of subheadings 8540.71 through 8540.79, inclusive General rate field: Free Simple ad-valorem rate parsed for planning: Free

Open official source

CBP CROSS rulings search for 8540.99.40.00

official-source · 2026-09-09

Search for binding CBP rulings involving similar merchandise. Capture ruling number, date, product facts, classification rationale, and whether the facts match this SKU. CROSS examples help frame broker questions but do not automatically classify your product.

Open official source

CBP Section 301 China-origin check for 8540.99.40.00

official-source · 2026-09-09

For China-origin goods, verify whether the HTS classification is covered by Section 301 remedies, whether any exclusion applies, and which Chapter 99 secondary classification should be reported. Do not infer coverage from the base HTS line alone.

Open official source

USTR Section 301 actions and exclusions for 8540.99.40.00

official-source · 2026-09-09

Check USTR Section 301 tariff actions, exclusion notices, and extension status. Save the specific list/exclusion evidence if a product exclusion is claimed.

Open official source

AD/CVD scope check for 8540.99.40.00

official-source · 2026-09-09

Search Commerce ACCESS/AD-CVD resources by country, product, case number, HTS number, and commodity. AD/CVD scope can be broader or narrower than an exact HTS match; ask the broker whether a scope ruling or specialist review is needed.

Open official source

CBP China/Hong Kong IEEPA and other remedy check for 8540.99.40.00

official-source · 2026-09-09

Review whether any current CBP trade-remedy FAQ, CSMS message, or Chapter 99 note applies in addition to Section 301, base duty, AD/CVD, or other measures. This is a prompt for professional review, not an automated determination.

Open official source