21It must therefore be ascertained, on the one hand, whether such an instrument entails an obligation to accept it as consideration or part consideration for a supply of goods or services and, on the other hand, whether that instrument or related documentation specifies the goods or services to be supplied or the identity of the potential suppliers thereof. As is clear from the wording of Article 30a(1) of the VAT Directive, which contains the conjunction ‘and’, and, as the Advocate General states in point 41 of her Opinion, the two conditions referred to in paragraph 20 of the present judgment are cumulative.