Every shipment in this category travels with four documents. Buyers routinely confuse two of them, and routinely accept a fifth that should not exist. Getting this right costs nothing and prevents the most expensive kind of delay — the one where your goods sit in a port accruing charges while a piece of paper is corrected by email.
The four documents that travel with every shipment
| Document | What it proves | Who issues it |
|---|---|---|
| Commercial invoice | The declared value and the terms of sale | The seller |
| Packing list | What is physically in each carton | The seller |
| MSDS | How the chemical content must be handled and transported | The resin producer, referenced by the seller |
| COA | The tested properties of a specific batch | The producer, per batch |
Note the pattern: only the first two are produced by the seller as a matter of course. The other two describe the material, and a seller who cannot obtain them is telling you something about where the material came from.
MSDS is not a certification
This is the most common misunderstanding in the category. An MSDS — more precisely an SDS — is a safety data sheet. It describes hazards, handling, storage and transport classification. It is a disclosure document, not an approval.
It does not mean the product has been approved by anyone. It means the hazards have been described. A supplier presenting an MSDS as though it were a compliance certificate is either confused or hoping you are.
Any kit containing resin should have an MSDS. If a supplier cannot supply one, the practical question is not "why not" but "can this ship at all".
COA and MSDS are not interchangeable
An MSDS describes the material in general. A COA describes one specific batch: what was tested, what the result was, on what date. An MSDS can be reused for years. A COA cannot, because it is tied to a production run.
If your market or your customer requires a COA, ask for it per shipment, not once. A COA from eighteen months ago describes eighteen-month-old material.
What we do not have, and why we say so
We hold two Chinese patents on the glass repair tool: utility model ZL 2012 2 0569312.0 and design patent ZL 2012 3 0526900.1. Those are real, registered and checkable.
We do not hold SGS, CE or RoHS certification for these kits. We could put those logos on a page and most buyers would not check. We do not, for a practical reason: a certificate that is not in the seller's own name will not survive your customer's audit, and when it fails it fails against you, not against us.
If your market requires CE marking, the honest path is to establish what testing is needed for your specific configuration and cost it in — not to accept a document that looks right.
Incoterms change who carries which risk
EXW, FOB and CIF place the boundary of responsibility in different places, and the document set changes accordingly. Under EXW the buyer arranges export clearance; under FOB and CIF the seller does. This is not a formality — if you buy EXW without an export agent, your goods can be legally unable to leave.
For a first order, FOB is usually the least ambiguous: the seller handles export clearance, the buyer controls the freight forwarder. Confirm which port — for this region, Ningbo or Shanghai.
A pre-shipment checklist
- Commercial invoice matches the PO: quantity, unit price, total, Incoterm, port.
- Packing list matches the physical cartons: count, dimensions, gross weight.
- MSDS present and current for every resin-bearing item.
- COA present if your market or customer requires it, and dated to this batch.
- Production date on cartons checked against the stated shelf life.
- Barcode and statutory pack text verified against a physical sample, not a PDF.
- Beneficiary name on the bank instruction identical to the contracting entity.
Every item on that list has, at some point, stopped a shipment. None of them takes more than a few minutes to check before the container is sealed.