Means either a SMETS1 ESME; or a device installed (or to be installed) at a premises, which:
(a) consists of the components or other apparatus identified in; and
(b) as a minimum, has the functional capability specified by and complies with the other requirements of,
the part(s) of the SMETS identified as applying to ‘Electricity Smart Metering Equipment’ (and, where applicable, the part(s) relevant to the Physical Device Type in question) in a Version of the SMETS which was within its Installation Validity Period on the date on which the device was installed.