A pint glass is a drinking vessel made to hold either a British pint of 20 fluid ounces (an "imperial pint") or an American pint of 16 fluid ounces. These glasses are used predominately to serve beer. The common shapes of pint glass are: In the United Kingdom, draught beer must be sold in Imperial measure (see Pint#Effects of metrication).
United Kingdom law requires certain steps be taken to ensure that a pint of beer is indeed a pint. Though this can be achieved using so-called "metered dispense" (calibrated pumps), the more common solution is to use certified one-pint glasses. Until recently these had a crown stamp and number etched upon them, however EU directives have stated that the glasses instead now, must have PINT with the letters CE etched on them, for synchronisation in the European Union (although the Conservatives have campaigned to have dual markings of crown and CE).
The number relates to the authority certifying the capacity of the glass. Selling beer in unmeasured glasses without using some other form of calibrated measure is illegal. Half-pint and one-third pint glasses are also available, and are subject to the same laws.