a) providing for common measures with which Member States shall undertake to comply in the fomulation of their Customs laws and procedures; 2. b) establishing appropriate institutional arrangements at regional and national levels; c) co-operating to prevent fraud and illicit trade. The provisions of this Annex do not apply to areas of Customs co-operation which are covered specifically by Annexes 1 and 4 of this Protocol. 3. Co-operation in Customs matters shall apply to any administrative authority of Member States which is competent for matters covered by Customs legislation. This co-operation shall be channeled through the Customs Authorities of Member States. ARTICLE 3 HARMONISATION OF CUSTOMS TARIFF NOMENCLATURES AND STATISTICAL NOMENCLATURES 1. Subject to the exceptions enumerated in paragraph 4: a) Each Member State undertakes, except as provided in sub-paragraph (c) of this paragraph, to adopt Customs tariffs nomenclatures and statistical nomenclatures which are in conformity with the Harmonised System. It thus undertakes that in respect of it Customs tariff and statistical nomenclatures ­ (i) it shall use all the headings and sub-headings of the Harmonised System without addition or modification, together with their related numerical codes;