Four documents do the work: the commercial invoice, the packing list, the certificate of origin and the transport document (waybill or bill of lading). What causes holds is almost never a missing document — it is documents that disagree with each other. The invoice value not matching the declared value, the packing list not matching what is in the box, part descriptions too generic for the tariff classification: those are the delays. Checking three things before dispatch — values, quantities and descriptions consistent across all documents — prevents most of them.
Table of Contents (7 points)
What each document is for
- Commercial invoice: what was sold, to whom, for how much. It is the basis for duty assessment, so the description has to be specific enough to classify.
- Packing list: what is physically in the shipment, carton by carton, with weights and dimensions. Customs opens against this list, not against the invoice.
- Certificate of origin: where the goods were made. It can change the duty rate under a trade agreement, and for some destinations it is required regardless.
- Transport document: the contract with the carrier. Under DDP the seller arranges it; under FOB you do.
The three consistency checks worth doing every time
- 01 Values: the invoice total, the declared customs value and the payment record agree.
- 02 Quantities: the packing list matches what is in the cartons, including partial reels and loose quantities.
- 03 Descriptions: each line says what the part is (function, package), not just a part number — a customs officer cannot classify an MPN.
Documents that are not customs documents but matter later
Datasheets and a certificate of conformance travel with the goods and become the reference if a quality question arises months later. Lot and date-code records are the same: not required for clearance, but they are what makes a traceability claim possible after the fact. On obsolete and hard-to-find lines, keep them with the shipment record rather than in a separate folder.
Export control is a separate question from customs
Some semiconductors and related technology are subject to export controls, and the obligation attaches to what the item is and where it is going — not to the shipping terms. It is worth knowing the classification of your parts before the first shipment rather than at the port, because a controlled item needs a licence regardless of how well the invoice is written. This is a legal question for the exporter and importer, not something a supplier's paperwork resolves.
Put this to work on your component list
Send the part numbers or the whole BOM sheet. Each line comes back with current spot availability, original manufacturer condition, and verified cross-references — packed and shipped together in one single parcel.
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How this guide is written
Written by the ICBOMS sourcing desk in Shenzhen and reviewed against the manufacturer documents and industry standards the guide cites. Statements are limited to what this desk does and how a part is judged — no indicative prices, lead times or stock counts, because those are quoted per line against a live check. Each guide carries the date it was last reviewed at the top of the page.