The customs union acquis consists almost exclusively of legislation which is directly binding on the Member States. It includes the EU Customs Code and its implementing provisions, the combined nomenclature, common customs tariff and provisions on tariff classification, customs duty relief, duty suspensions and certain tariff quotas, and other provisions such as those on customs control of counterfeit and pirated goods, drugs precursors, export of cultural goods as well as on mutual administrative assistance in customs matters and transit. Member States must ensure that the necessary implementing and enforcement capacities, including links to the relevant EU computerised customs systems, are in place. The customs services must also ensure adequate capacities to implement and enforce special rules laid down in related areas of the acquis such as external trade.