Back Up Ring
CN β US| HS Code | Tariff Rate | Origin | Destination | Doc |
|---|---|---|---|---|
| 3926904590 | 38.5% | CN | US | Official Doc |
| 3926909989 | 22.8% | CN | US | Official Doc |
| 4016931050 | 37.5% | CN | US | Official Doc |
| 4016935050 | 37.5% | CN | US | Official Doc |
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π‘οΈ Back Up Rings (Backup Seals)
π HS Code Reference & Customs Clearance Guide | 2026 Latest Tariff Analysis | Professional Clearance Strategy
π I. Product Definition & Classification: What Exactly is a "Back Up Ring"?
A Back Up Ring (also known as a Backup Ring or Support Ring) is a critical auxiliary component used in hydraulic and pneumatic systems. Its primary function is to prevent extrusion (squishing) of the primary elastomeric seal (such as an O-ring) into the clearance gap under high pressure.
In international trade, these rings are classified not as "seals" in the generic sense, but as articles of vulcanized rubber or plastics, depending on their material composition. They are often grouped under "Gaskets, washers and other seals" for tariff purposes, but the specific sub-heading depends heavily on the material (Rubber vs. Plastic) and the application (Automotive vs. General Industrial).
β οΈ Key Distinction Point:
- Rubber Backup Rings: Typically made of NBR, FKM, or Silicone. Often used in automotive or heavy-duty hydraulics.
- Plastic/Polymer Backup Rings: Typically made of PTFE, Nylon, or POM. Used in high-pressure industrial applications.
- Application Specificity: If used exclusively in automotive goods (Chapter 87), specific automotive sub-codes may apply for rubber versions.
π¦ II. HS Code Classification Details (2026 Latest Tariff Authority Comparison)
| HS Code | Product Description | Material | Application Context | Tax Rate (Total) |
|---|---|---|---|---|
4016.93.10.50 |
Rubber: Gaskets, washers and other seals: Of a kind used in the automotive goods of chapter 87 | Vulcanized Rubber (Non-Hard) | Automotive Hydraulics/Pneumatics | 27.5% |
4016.93.50.50 |
Rubber: Gaskets, washers and other seals: Other Other | Vulcanized Rubber (Non-Hard) | Industrial/General Hydraulics | 27.5% |
3926.90.45.90 |
Plastic: Gaskets, washers and other seals Other | Plastics (Headings 3901-3914) | High-Pressure Industrial Seals | 0.0% |
3926.90.99.89 |
Plastic: Other Other (Non-Seal Specific) | Plastics (Headings 3901-3914) | General Plastic Articles | 12.8% |
π Critical Note:
- Rubber Backup Rings are highly taxed (27.5%) regardless of whether they are automotive-specific (4016.93.10.50) or general industrial (4016.93.50.50).
- Plastic Backup Rings offer significant tax advantages if correctly classified under3926.90.45.90(0.0% total tax).
- Misclassifying a plastic backup ring as a general plastic article (3926.90.99.89) incurs a 12.8% tax.
π° III. 2026 Latest Tariff Rate Detailed Explanation (Including Surtaxes & Policy Additions)
β Applicable Country: United States (US)
β Country of Origin: China (CN)
β Effective Date: 2025/2026 (Based on current 301/IEEPA frameworks)
π― 1. 4016.93.10.50 & 4016.93.50.50 ββ Rubber Backup Rings
| Item | Content |
|---|---|
| Base Duty Rate | 2.5% (Ad Valorem) |
| Additional Duty (Section 301/IEEPA) | +25.0% |
| Total Effective Rate | 27.5% |
| Tax Calculation | CIF Value Γ 27.5% |
| De Minimis Exemption? | β No (Denied for goods under this HTSUS prefix originating in China) |
| Legal Basis Path | USITC:4016.93 β FOOTNOTE:301 β IEEPA:9903 |
π Explanation:
- The 2.5% base rate is standard for "Other articles of vulcanized rubber other than hard rubber."
- The 25% surtax is applied under Section 301 of the Trade Act, specifically targeting Chinese-made rubber components.
- No distinction is made between "automotive" (4016.93.10.50) and "other" (4016.93.50.50) rubber rings for tariff rates; both bear the full 27.5% burden.
- This is a high-cost item for importers. Cost optimization strategies must be considered.
π― 2. 3926.90.45.90 ββ Plastic Backup Rings (Gaskets/Seals)
| Item | Content |
|---|---|
| Base Duty Rate | 0.0% |
| Additional Duty (Section 301/IEEPA) | 0.0% |
| Total Effective Rate | 0.0% |
| Tax Calculation | CIF Value Γ 0.0% |
| De Minimis Exemption? | β Yes (if value < $800) |
| Legal Basis Path | USITC:3926.90.45 β HTSUS Note 1 |
π Explanation:
- Plastic seals/gaskets (3926.90.45) are currently exempt from the 301 surtax and have a 0% base rate.
- This is a major cost-saving opportunity if the backup ring material allows for plastic (e.g., PTFE-filled, Nylon).
- Verification: Ensure the product is explicitly a "seal" or "gasket" to qualify for3926.90.45.90, not3926.90.99.89.
π― 3. 3926.90.99.89 ββ Plastic Backup Rings (Misclassified/General)
| Item | Content |
|---|---|
| Base Duty Rate | 5.3% |
| Additional Duty (Section 301/IEEPA) | +7.5% |
| Total Effective Rate | 12.8% |
| Tax Calculation | CIF Value Γ 12.8% |
| De Minimis Exemption? | β No (For China-origin goods) |
| Legal Basis Path | USITC:3926.90.99 β FOOTNOTE:301 |
π Explanation:
- If the customs broker fails to identify the product as a "seal/gasket" and classifies it as a "general plastic article," the 7.5% surtax applies.
- Always provide product descriptions emphasizing "seal" or "gasket" functionality.
π οΈ IV. Customs Clearance Practical Advice (Battle-Tested Pitfall Avoidance)
β 1. Documentation Checklist (Mandatory)
| Document | Required | Description |
|---|---|---|
| β Product Specification Sheet | βοΈ | Must state material (Rubber vs. Plastic), hardness, and dimensions. |
| β Material Safety Data Sheet (MSDS) | βοΈ | To prove chemical composition (e.g., PTFE, Nylon, NBR). |
| β Product Photos | βοΈ | Clear images showing the ring structure and any markings. |
| β Commercial Invoice | βοΈ | Must use terms like "Backup Ring, Plastic, for Hydraulic Seal" or "Rubber Backup Ring for Automotive". |
| β Bill of Lading | βοΈ | Consistent with invoice description. |
β 2. Declaration Strategy (Key Mnemonics)
π₯ "Material Matters: Plastic Low, Rubber High; Seal Keyword is King!"
| Scenario | Correct Declaration | Incorrect Declaration | Result |
|---|---|---|---|
| PTFE Backup Ring | "Plastic Backup Ring, Seal for Hydraulic System" | "Plastic Ring" | Avoids 12.8% β 0% Tax |
| NBR Rubber Ring | "Rubber Backup Ring, Automotive Grade" | "Rubber Part" | Correctly assigns 27.5% (No savings, but accurate) |
| Mixed Shipment | Separate HS Codes for Plastic vs. Rubber | Combine all as "Rubber Parts" | Over-taxation of plastic items |
β 3. Special Handling Cases
| Scenario | Recommendation |
|---|---|
| Plastic vs. Rubber | Switch to Plastic if possible. PTFE or Nylon backup rings can offer significant cost savings (0% vs. 27.5%). Consult with engineers. |
| Automotive Specific | Even if used in automotive, rubber backup rings (4016.93.10.50) still face 27.5%. No exemption for automotive rubber seals from China. |
| Kit Sets (O-ring + Backup Ring) | Declare separately. If mixed, the higher tax rate may apply to the entire shipment unless carefully split. |
| Origin Marking | Ensure "Made in China" is clearly marked. US Customs uses this to trigger surtaxes. |
π V. Global Market Customs Comparison (2026 Latest)
| Country/Region | Recommended HS Code | Tariff (China Origin) | Certification Required | Notes |
|---|---|---|---|---|
| πΊπΈ USA | 3926.90.45.90 (Plastic) 4016.93.50.50 (Rubber) |
0.0% (Plastic) 27.5% (Rubber) |
None (Non-Hazardous) | Biggest risk: Misclassifying plastic as general goods. |
| π¨π³ China | 3926.90.90 / 4016.93 |
Varies (Export Duty Low) | N/A | Exporters should focus on accurate origin documentation. |
| πͺπΊ EU | 3926.90.97 (Plastic) 4016.93 (Rubber) |
0% (Plastic) 4% (Rubber) |
REACH Compliance | EU does not impose 301-style surtaxes. |
| π¨π¦ Canada | 3926.90.90 / 4016.93 |
0% (Plastic) 5% (Rubber) |
CFIA (if food grade) | Similar to US, but lower rubber duties. |
π Conclusion:
- USA is the most punitive market for rubber backup rings (27.5%).
- Plastic backup rings are tariff-free in the US, making them a strategic alternative.
- EU and Canada offer much more favorable rates for rubber seals (~4-5%).
π VI. Common Mistakes & Pitfall Guide (Lessons Learned)
β Mistake 1: Declaring PTFE Backup Rings as "Plastic Parts" (3926.90.99.89)
π Consequence: 12.8% tax instead of 0.0%. $12.80 extra per $100 value.
π Fix: Use keyword "Seal" or "Gasket" in description.
β Mistake 2: Assuming all rubber rings are taxed equally
π Consequence: No savings, but accurate. However, misclassifying as "hard rubber" (4016.95) can lead to different codes, though currently similar.
π Fix: Stick to 4016.93 for vulcanized non-hard rubber.
β Mistake 3: Mixing Plastic and Rubber Backup Rings in one HS Code
π Consequence: Customs may audit the entire shipment, delaying clearance.
π Fix: Separate shipments or clearly distinguish on the invoice.
β Correct Practice:
"Back Up Ring, PTFE, 10mm OD, for Hydraulic Cylinder Seal β Plastic Seal Article"
π― VII. Conclusion: Professional Declaration, Cost Savings, Efficiency!
π― Remember the Golden Rules:
πΉ "Plastic is King: 0% Tax if Declared as Seal."
πΉ "Rubber is Costly: 27.5% Surtax Applies regardless of Application."
πΉ "Keywords Matter: Use 'Seal' or 'Gasket' to qualify for3926.90.45."
π Pro Tip:
If your design allows, specify plastic (PTFE/Nylon) backup rings for high-volume imports to the US. This can save 27.5% in duties compared to rubber alternatives. Always request a Pre-Ruling from US Customs (CBP) for complex hybrid kits.
π£ Immediate Action:
π Consult your supply chain engineer: "Can we switch to PTFE backup rings?"
π Update your product database: Ensure 'Seal' is in the description.
π Achieve 0% Duty on plastic backup rings β Profit Margin Boost!
β¨ Professional Clearance Starts with Accurate Classification!
πΌ Every Cent Saved is Profit Earned!
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About HS Code Classification
The Harmonized System (HS) is an internationally standardized nomenclature developed by the World Customs Organization (WCO) to classify traded products. Over 200 countries use the HS system as the basis for customs tariffs, trade statistics, and import/export regulations.
Each HS code follows a hierarchical structure:
- Chapter (2 digits) β Broad category of goods (e.g., Chapter 84: Machinery and Mechanical Appliances)
- Heading (4 digits) β More specific grouping within the chapter
- Subheading (6 digits) β Internationally standardized breakdown, used by all WCO member countries
- National subdivisions (8-10 digits) β Country-specific extensions for further classification, such as US HTSUS 10-digit codes
Correct HS code classification is essential for smooth customs clearance, accurate duty payment, and compliance with trade regulations. Misclassification can lead to customs delays, overpayment of duties, or penalties.
When importing from CN to US, the applicable tariff rates may include:
- Most-Favored-Nation (MFN) rate β The standard duty rate applied to WTO members
- General rate β Applied to countries without trade agreements
- Trade remedy duties β Additional tariffs such as Section 301 (anti-dumping), Section 232 (national security), or countervailing duties
The information provided on this page is for reference purposes only. For official classification, please consult with your local customs authority or a licensed customs broker.