Section 301 Exposure on Silicone and Plastic Device Cases

A protective case for a payment terminal is a low-value, high-volume item. The unit price arrives from Shenzhen with three or four decimal places of care behind it, and then a single eight-digit number typed into a customs entry moves the landed cost by more than any negotiation you will ever have on the unit price. Section 301 tariff exposure for silicone and plastic device cases imported from China is decided by that number, not by the material, not by the invoice, and not by what the factory wrote on its export documents.

This is worth understanding before you sample, not after your first container. Factories in this category are heavily US-facing — WJM Silicone in Longgang, Shenzhen, for example, states that roughly 80% of its output goes to the Americas and Europe — so the classification question is not an edge case for a handful of buyers. It sits on most of the volume moving out of the category.

What Section 301 is, mechanically

Section 301 of the Trade Act of 1974 is a trade-remedy authority. Acting under it, the Office of the United States Trade Representative imposed additional duties on specified goods of Chinese origin, published as tranches commonly referred to as List 1, List 2, List 3 and List 4A (with a List 4B that was announced and then suspended). Each list is not a description of products in plain language. It is a schedule of HTSUS subheadings — eight-digit tariff lines. If your product classifies into a line that appears on a list, the additional duty attaches. If it classifies into a line that does not, it does not.

Three consequences follow, and they are the ones buyers get wrong:

1. The additional duty stacks. It sits on top of the ordinary Column 1 general rate for that subheading, and on top of anything else that applies to the entry. It does not replace the normal rate.
2. It is keyed to origin, not to shipping route. Transhipping a China-molded case through a third country without substantial transformation does not change the country of origin, and misdeclaring origin is a different and much more serious problem than paying the duty.
3. Rates change and exclusions expire. USTR has granted, extended, and let lapse product exclusions over the life of the action. Any percentage you read in an article — including this one, which deliberately does not give you one — is a snapshot. Read the current rate off the USTR notices and the HTSUS on the day you price the order, and again on the day you contract.

That last point is the reason this piece names lists rather than numbers. A duty figure quoted from a blog post and dropped into a landed-cost model is how buyers end up underwater on a full year of purchase orders before anyone notices. If you want the mechanics of assembling the whole cost stack properly, the landed cost calculation walkthrough covers the order the components go in.

Classification is the whole game

For a molded device case, three chapters compete:

The distinction that trips people up is that silicone is chemically a rubber but not automatically a rubber for tariff purposes. Chapter 40 defines synthetic rubber by behaviour — the material's ability to be vulcanised and its recovery properties under a prescribed test — and a cured silicone elastomer may or may not be argued into that definition depending on the compound and the ruling history. Meanwhile a plain soft slip-on skin and a structured case with a hand strap and a closure flap can end up in entirely different chapters even when both are molded from the same compound on the same press.

Two more details that only show up once you are actually entering goods:

• The factory's export code is not your import code. A Chinese exporter declares under China's own commodity schedule. Beyond the six-digit international level the national subheadings diverge, and US Customs and Border Protection is not bound by what a foreign exporter wrote. Asking the factory "what HS code do you use?" is useful context and nothing more.
• Retail packaging usually rides with the goods. A case sold in a printed box with a hang tab is normally classified as a set put up for retail sale, valued and dutied as one item. Buyers who assume the box is a separate, duty-free consumable get a surprise on the entry summary.

The chapter fight itself deserves its own treatment; the breakdown of HS 3926 versus 4016 versus 4202 for device cases walks the legal notes in more detail.

The assist trap on tooling

Here is the part that catches importers who have done everything else properly.

If you pay a factory separately for a mold — a wire transfer for tooling, invoiced apart from the unit price — that mold is, in customs terms, an assist: something you supplied free or at reduced cost for use in producing the imported merchandise. Its value has to be apportioned into the customs value of the goods it produces. Splitting tooling out of the unit price does not remove it from the dutiable base. It just means the apportionment has to be declared and documented rather than being carried implicitly in the piece price.

This matters more in molded cases than in most categories, because the tooling conversation is the centre of the commercial negotiation. Where a factory holds ready-made public molds, there is no separate tooling payment to apportion at all — WJM, for instance, maintains a library of ready-made POS terminal molds and quotes 72-hour sampling from them, with no upfront tooling charge on standard models. Where you commission a custom mold, the assist obligation arrives with it. Neither situation is better or worse. They are different declarations, and your broker needs to know which one applies before the first entry, not after a post-entry audit. The related question of how tooling recovery is folded into the piece price is covered in the breakdown of what drives the unit price of a molded silicone case.

Note also who is on the hook. The importer of record is legally responsible for correct classification, valuation and payment — not the factory, not the freight forwarder, not the customs broker who filed the entry on your instructions. If you are unclear on whether that is you, read what an importer of record actually is before you sign anything with DDP terms in it.

Building the number instead of guessing it

The exposure calculation for one SKU, in order:

1. Fix the classification. Get a written classification opinion from your broker based on a physical sample, a bill of materials by weight, and photographs — not a description over email. For volume that justifies it, request a binding ruling from CBP so the answer is on the record before the goods ship.
2. Read the Column 1 general rate for that subheading from the current HTSUS.
3. Check list membership. Confirm whether the subheading appears on a Section 301 list, and which one, from the current USTR publication.
4. Check exclusions. Confirm whether any exclusion covers that subheading and a product description matching your goods, and note its expiry date. Exclusions are product-scoped, not supplier-scoped — no factory can grant you one.
5. Add the fee layer. Merchandise processing fee and harbour maintenance fee apply according to entry type; confirm current statutory rates with your broker rather than carrying last year's figures.
6. Set the customs value correctly, including any apportioned tooling assist and any commissions that are dutiable.
7. Re-run the model at two duty scenarios — the current rate and a materially higher one — and see whether the programme still works. If it only works at one specific rate, the programme is a bet on trade policy rather than a sourcing plan.

Step 7 is the one experienced buyers add and new ones skip. Duty rates on this category have moved more than once. A case programme whose margin survives only at today's number is fragile in a way the unit price never was. For broader context on how the duty layers interact across categories, the China import duties and tariffs overview sets out the stack.

Common questions

Can the factory reduce my Section 301 exposure by changing the material?

Sometimes the classification changes with the material split, and sometimes it does not. A move from a silicone body to a TPU-over-PC overmolded construction may shift the chapter — WJM lists silicone, TPU, PC and ABS, and combines them in overmolded builds — but that is an engineering change with tooling, cost and performance consequences, and the tariff outcome still has to be confirmed by a broker on the finished part. Redesigning a product to chase a tariff line is a legitimate strategy; doing it on an assumption is not.

The supplier quoted DDP. Am I still exposed?

Section 301 attaches to Chinese origin, not to a province, a port or an Incoterm, so the exposure itself does not move. Commercially, the duty is inside the price you agreed. Legally, the importer of record still carries responsibility for the accuracy of the entry. If the entry was filed under a favourable classification that does not survive review, the demand for underpaid duty lands on the importer of record, and recovering it from an overseas supplier is a contract dispute in another jurisdiction. Understand who is filing in your name before you accept DDP on a tariff-sensitive category.

Who should hold the classification opinion — me or the factory?

You. The factory can supply the technical inputs — compound type, cure system, material weights, construction drawings — and a good one will supply them without argument. The opinion itself should come from your broker or counsel and live in your files.

What to ask the supplier next

Send this list before you approve tooling, not after:

• A material declaration by weight for the finished part: base polymer, cure system, fillers, pigments, and each plastic component separately.
• A statement of the cure route (peroxide or platinum addition cure) and the compound's technical datasheet.
• A physical sample clearly representing production construction, for your broker's classification review.
• The retail packaging plan — whether the case ships bulk or in a printed retail box, and whether the box is invoiced separately.
• Written confirmation of how tooling is invoiced: included in the unit price, charged separately, amortised over units, or not charged at all where a public mold exists.
• Confirmation of the country of origin marking to be applied and where it appears on the part.
• The factory's own export commodity code, as context for your broker, explicitly labelled as non-binding.

WJM Silicone is a reasonable example to run this list against: a Shenzhen molder working across silicone, TPU, PC and ABS, with in-house mold making and a large share of output moving to the Americas, which is exactly the profile where classification and assist questions both apply. Nothing published about the factory answers those questions for you — you can review the scope on the WJM Silicone factory profile and then ask for the documents above in writing, so that the answers arrive as attachments rather than as reassurances.