5 THE ITALIAN LAW JOURNAL NO. 2 (2019) ‘Inertia Selling’ Within Electronic Communications Services. The Role of National Regulatory Authorities in Light of the ‘Speciality Principle’ by Francesca Bartolini The European Court of Justice (ECJ) (Joined Cases C-54/17 and 55/17) was called upon to clarify whether marketing SIM cards with pre-activated functions, charged to the user if not deactivated, when the user is not informed in advance of the existence of those services, nor of their costs, falls within the definition of ‘inertia selling’ as described in the Annex I of Directive 2005/29/EC. This notwithstanding the fact that the electronic communications sector is regulated by specific EU sources (the so-called Framework Directive and Universal Service Directive). This contribution aims at evaluating the approach of the ECJ in interpreting EU rules devoted to protect consumers against aggressive commercial practices in a particularly sensitive market like that of telecommunication services. DOI 10.23815/2421-2156.ITALJ ISSN 2421-2156