Car accessories sold online come back for two main reasons: they do not fit the customer’s vehicle, or they arrive damaged. Both are decided at the factory, months before the first listing goes live — by what is printed on the box, how the part is packed, which barcode it carries and what the instructions say.

This guide is for online sellers and brands preparing a private-label range for marketplaces. It covers who allocates the barcode, what marketplaces say about product identifiers and fitment, how to pack long, flat, brittle or heavy accessories for parcel networks, and what the instructions and photographs need to show. Marketplace rules below are only those we could confirm on each marketplace’s own pages; rules change, so check the current help pages for your category before you list.

💬 Preparing a car accessory range for online sale? We can brief the factory on barcodes, box labels and packaging before production. Talk to us about car accessory OEM.

Fix the listing data before anything is printed

Decide your SKUs, barcodes and fitment summary before the factory prints packaging, because each of them appears on the box and is expensive to change afterwards.

Packaging print runs have their own minimums, and relabelling cartons after arrival costs time and often money. The data that goes on the box should therefore come from the same master record that feeds your listings:

  • one SKU for each distinct part, including left and right, drive-side and colour variants
  • one barcode per SKU
  • a short fitment line per SKU: vehicle, model code, production period, body style, drive side
  • the language versions you need for each market

If your fitment is not yet defined at configuration level, start there; our guide to car accessory fitment data explains how to build the table.

Barcodes: who allocates the GTIN

Under GS1 rules, the brand owner allocates the barcode number (GTIN), so a company that has products made in any country and sells them under its own brand allocates the GTINs for its range.

The GS1 General Specifications (Release 26.0, January 2026) call the responsible party the “GTIN allocator” and treat it as equivalent to the brand owner. They list, among others, the party that manufactures a trade item or has it manufactured in any country, an importer or wholesaler that sells under its own brand name or changes the trade item (for example its packaging), and a retailer that sells under its own brand name.

The same text sets the rules that matter for a private-label range:

Rule (GS1 General Specifications)What it means for car accessories
A trade item shall be assigned a GTIN before it is offered for saleAllocate barcodes before you list, not after
Each trade item different in design or content gets a unique numberLeft and right, RHD and LHD, colour and model variants each need their own
A separate GTIN is needed whenever trade item declarations differ in a way relevant to tradingA different fitment or pack content is a different item
A downstream party may not assign a different GTIN to an item that already has one, unless the item changes in a way that requires a new GTINBuying a factory’s stock item unchanged means using its existing barcode, if it has one

GS1’s GTIN Management Standard (Release 1.1, September 2023) then sets when a change needs a new number. Among its rules: a change to the primary brand on the item, a change of more than 20% to a physical dimension or gross weight, and a change to the number of items in a case all require a new GTIN at the relevant level. Its guiding principle is that a new GTIN is required when at least one of three things applies: consumers or trading partners are expected to tell the products apart, there is a regulatory or liability disclosure requirement, or the supply chain is substantially affected.

GTINs come from a GS1 Company Prefix or individual identification keys licensed by a GS1 Member Organisation. Contact the GS1 organisation in your own country.

What marketplaces say about product identifiers

Marketplaces generally expect valid GS1 product identifiers, and some check them against the GS1 database, so buying cheap numbers from a reseller is a risk.

  • Walmart Marketplace states that it requires product IDs for all items, that it checks them by cross-referencing the GS1 database, that IDs not recognised by GS1 are treated as invalid, and that listings with invalid IDs will be removed. It recommends obtaining product IDs directly from GS1.
  • Amazon’s seller guide says that if you create and own a new product yourself, you can get a GTIN through GS1, and that where a product cannot be matched to an existing listing you may be eligible for a GTIN exemption, applied for with images showing all sides of the product and its packaging.

Requirements differ by category and change over time. Check the current help page for your category before the factory prints the barcode.

Fitment on the listing

Put fitment into the marketplace’s structured compatibility fields, not only into the description, and treat its accuracy as your responsibility.

eBay’s Seller Center describes fitment as information identifying which vehicle a part fits, entered by year, make, model, trim and engine, or by choosing a product from eBay’s parts catalogue (available in Car & Truck Parts & Accessories categories). It states that compatibility information in the description may not be surfaced in search, and that the seller is responsible for presenting accurate information about compatible vehicles.

eBay Australia’s seller centre adds detail that shows why accuracy pays:

  • a listing can carry up to 1,000 or 3,000 vehicle combinations depending on the category
  • items that are not vehicle-specific should be marked with the “universal fitment” item specific
  • buyers can open a return with the reason “Doesn’t fit my vehicle”, which sellers must accept even with a no-returns policy
  • where the listing carries compatibility information, eBay covers the return label and removes the return from the seller’s “Not as Described” rate

Other marketplaces handle fitment in their own ways. Whatever the channel, export the compatibility data from your fitment table rather than typing it by hand, and keep the same configuration wording on the box label so the warehouse can pick the right variant.

💬 We can ask factories in Taiwan, Thailand and Malaysia to print your SKU, barcode and fitment line on each box and carton. See our car accessory OEM service.

Packaging that survives parcel networks

Car accessories are long, flat, curved, brittle or heavy, so packaging for parcel delivery should be specified by product type and checked against a recognised transit test.

Factory export cartons are designed to travel on a pallet in a container. A single unit in a parcel network is dropped, stacked and vibrated on its own. Packaging that is fine in the first case often fails in the second.

Product typeTypical damage in parcel deliveryPackaging point
Door visors, window louvresCracked acrylic, snapped ends, scratchesRigid box, end protection, film on visible faces
Bonnet guardsCracking at mounting points, scratched gloss surfaceShaped support so the curve is not flattened
Floor mats, cargo linersCreases from folding, deformation in heatRoll or flat-pack as the material allows; avoid hard folds
Mud flapsBent brackets, missing hardwareFixings bagged and secured inside the box
Side steps, roof racksBent ends, punctured cartons, heavy-parcel handlingEnd caps, internal bracing, weight marked on the carton

The International Safe Transit Association (ISTA) publishes test procedures for this. Its procedure 3A covers individual packaged products shipped through a parcel delivery system at 150 lb (70 kg) or less. ISTA also lists member procedures developed for a marketplace’s own distribution system, such as a “Ships in Own Container” test.

Write the packaging standard into the purchase order: box construction, inner protection, the test the pack should pass, and who carries out the test. Check packed units at pre-shipment inspection; our note on pre-shipment inspection and AQL explains how to set the sample size.

Instructions and the box insert

Instructions should be written for the customer fitting the part at home, in the languages of every market you sell into, and checked by someone actually fitting the part.

Most fitting complaints come from steps the instructions skipped. A useful insert covers:

  • a parts list with a picture of each item, so missing hardware is noticed before fitting starts
  • the vehicle configuration the part is for, matching the box label
  • surface preparation, for taped parts: cleaning and degreasing, and the conditions the tape needs to bond
  • step-by-step fitting with photographs or drawings, not text alone
  • what to check after fitting and periodically, and when to stop using the part
  • your company name and contact details for questions

Have the draft tested by someone fitting a sample to a real vehicle, following only the written steps. As the seller you may carry product liability for what you sell; our overview of car accessory OEM explains how that works in Japan and the EU. Also check the labelling and product-safety rules of each country you sell into against their current official texts.

Photographs that reduce returns

Product photos should show how the part fits and what is in the box, and should not show vehicle makers’ logos or another company’s images.

Photographs that reduce “does not fit” returns show the mounting points, the part fitted in place, the shape from more than one angle and the full contents of the box. A photo with a scale reference helps for universal items.

Two cautions. Vehicle makers’ badges and logos are trademarks; frame or retouch photos so your listing does not appear to be the vehicle maker’s product. And a factory’s catalogue photos belong to the factory or to whoever took them: get written permission or take your own. Your products should carry your own brand only; we do not arrange products that copy original-equipment designs or carry vehicle makers’ logos.

Sunsho Trade is a trading company and does not own factories. For each range we find and manage the right factory in Taiwan, Thailand, Malaysia or elsewhere, and brief it on barcodes, labels, packaging and inserts before production.

💬 Want your packaging, barcodes and inserts agreed with the factory before the first order? Send us your SKU list and target marketplaces. Send us your range.

For item-by-item detail, see our guides to mud flaps, bonnet guards, cargo liners, window louvres and spoilers, side steps and roof racks.

Frequently asked questions

1. Can I use the factory’s barcode on my private-label product?
Under GS1 rules, the party selling the item under its own brand allocates its GTIN. If you sell the product under your brand, plan to allocate your own GTINs from your GS1 licence.

2. Do left and right parts need separate barcodes?
Yes, if they are sold as separate items, because each item that differs in design or content gets its own GTIN. A left-right pair sold together in one box is a single item with one GTIN.

3. Is it safe to buy barcodes from a reseller website?
It carries risk. Walmart Marketplace, for example, checks product IDs against the GS1 database and removes listings with IDs that GS1 does not recognise. Obtain numbers from the GS1 organisation in your country.

4. Does fitment written in the description count?
eBay states that compatibility information in the description may not be surfaced in search. Use the structured compatibility fields where the marketplace offers them, and keep the description consistent with them.

5. Which packaging test should I ask the factory for?
For single units sent by parcel, ISTA procedure 3A is a common reference, and some marketplaces have their own ISTA procedures. Confirm what your marketplace and logistics provider require, then write it into the purchase order.

Sources

Checked on 24 October 2026.