1. No Member State may prevent, prohibit or restrict the placing on the market or entry into service of a measuring instrument (hereinafter called "instrument") or of ancillary equipment if that instrument or equipment bears the mark certifying initial verification or the sign certifying EEC pattern approval as provided for in Articles 10 and 11.
2. "Measuring system for liquids" means a measuring instrument comprising, as well as the meter itself and the ancillary equipment which may be associated with it, all the devices necessary for ensuring correct measurement and any devices which have been added in order, in particular, to facilitate the operations.
