To allow transparency and comparability of contractual arrangements and their on- going monitoring, the register of information focuses on the operational links between the financial entitiesas defined in Article 2, points (a) to (t) and the ICT third-party service providersan undertaking providing ICT services. This is enabled by using four keys, which, among others, serve to link relevant data to each other across the templates of the register of information: (i) the contractual arrangement reference number between the financial entity signing the contractual arrangement and the direct ICT third-party provider, (ii) the legal entity identifier (LEI) of financial entitiesas defined in Article 2, points (a) to (t) and the ICT third-party service providersan undertaking providing ICT services, (iii) the function identifier and (iv) the type of ICT servicesdigital and data services provided through ICT systems to one or more internal or external users on an ongoing basis, including hardware as a service and hardware services which includes the provision of technical support via software or firmware updates by the hardware provider, excluding traditional analogue telephone services.