administrative letter sent to the notifying parties confirming informally and normally without any reasoning either: — that the Commission sees no grounds for action against an agreement under Article 81(1) of the EC Treaty, because it does not restrict competition and/or affect trade between Member States (negative clearance-type comfort letter), or — that the agreement fulfils the conditions for granting an exemption under Article 81(3) of the EC Treaty (exemption-type comfort letter)