Under the EU Measuring Instruments Directive (Directive 2004/22/EC), the certification of measuring instruments and devices used in trade (including beer mugs, weighbridges, petrol pumps and the like) can be done by third parties anywhere within the EU with governments taking "only the legislative and enforcement (market surveillance) functions" and "ensuring that the system of third party assessment ... has sufficient technical competence and independence" (or, in simple language, calibration services were privatised). Glasses that have been certified by authorised firms anywhere within the EU have the letters CE etched on with the certifying agency's identification number.