In the United Kingdom, milk sold to the door is mainly measured in Imperial pints (but labelled 568ml), because the glass bottles are 'returnable', which means they were excluded from metrication. However, sterilized milk sold to the door is in 500ml glass bottles (and is 'non-returnable' and has colour coded lids that match the colour codes normally seen on plastic bottles). Often, in supermarkets they are sold in pints but labelled with their metric equivalent (568ml). Quantities larger than a pint are generally sold in metric units or multiples of a pint.