Imported and exported goods must be declared under specific subheadings or subdivisions of the Combined Nomenclature or of other nomenclatures they fall under, via the Classification Information System (CLASS). This determines the rate of customs duty of the Common Customs Tariff, or which non-tariff measures apply. The easy-to-use eLearning course CLASS System is based on the Union Customs Code and is produced by the European Commission Directorate General for Taxation and Customs (TAXUD) under the Customs Programme.

The Combined Nomenclature (CN) is a tool for classifying goods, set up to meet the requirements of the Common Customs Tariff and the EU's external trade statistics. It forms the basis for the declaration of goods; at importation or exportation or when subject to intra-Union trade statistics. This determines which rate of customs duty applies and how the goods are treated for statistical purposes. Other legislation may also refer to the Combined Nomenclature. The CN is thus a vital working tool for business and the Member States' customs administrations. The Combined Nomenclature was established by Council Regulation (EEC) No 2658/87 on the tariff and statistical nomenclature and is updated every year.

This easy-to-use eLearning module provides on overviewabout the Union Customs Code (UCC).