Insulated containers, eutectic plates and wheeled bases arrive together in one order, yet the declaration wants each item separately. Under Article 113 of the Customs Regulation, those who sign the declaration are responsible for the accuracy of the declared information and the attached documents, so the documents agreeing with one another comes first.

DocumentWhat it should carry
Commercial invoice (Article 115)Description, quantity and unit price of the goods; type, mark, number and count of the packages
Packing listContents, count, dimensions and weight per package
Catalogue page, dimensions tableNot attached to the declaration; kept ready to verify the description

Under Article 114, only the documents announced by the Ministry of Trade are attached to the declaration; the others are kept and shown to customs on request. Whether a wheeled base arriving with a container counts as part of the container or as a separate product depends on the invoice and the packing list telling the same story. Spares can travel in the same shipment; what matters is that they are separate lines on the packing list. A customs broker prepares the declaration; you supply the product description and the technical data.