It is required by law to have your glasses officially CE marked (Conformité Européenne, which is French for “European Conformity.” ) if you are using your cups in licensed establishments, such as pubs, restaurants, beer festivals and cider festival etc. This ensures that you are complying with the laws on the service of alcohol – ensuring that you are selling the correct volume. The CE measurement mark can be to the brim or a line marked on the unit.