Opinion of Advocate General Tanchev delivered on 15 July 2021.#SPV Project 1503 Srl and Others v YB and Others v YX and ZW.#Requests for a preliminary ruling from the Tribunale di Milano.#Reference for a preliminary ruling – Directive 93/13/EEC – Unfair terms in consumer contracts – Principle of equivalence – Principle of effectiveness – Payment order and attachment proceedings against third parties – Force of res judicata implicitly covering the validity of the terms of an enforceable instrument – Power of the court hearing the enforcement proceedings to examine of its own motion the potential unfairness of a term.#Joined Cases C-693/19 and C-831/19.