With a few exceptions, such as coffee, tea and mixed drinks, every glass served in a German bar or restaurant must carry a fill line, sometimes several. Germans call it the Eichstrich, the calibration line. Its correct name is Füllstrich. It marks exactly how much the customer has paid for, and the foam does not count. If the drink stops below the line, the guest may complain. The guest can ask for the missing beer to be poured or refuse the glass. The rule rests on the federal Measurement and Calibration Act and its ordinance.