Single malt whisky is a whisky made at one particular distillery from a mash that uses only malted grain, ordinarily barley. Single malts are typically associated with single malt Scotch, though they are also produced in various other countries. Under Scotch Whisky Regulations, a "Single Malt Scotch Whisky" must be made exclusively from malted barley, must be distilled using pot stills at a single distillery, and must be aged for at least three years in oak casks of a capacity not exceeding 700 litres. These constraints may not apply to whisky marketed as single malt that is produced elsewhere. For example, there is no definition of the term single malt in the law of the United States, and some American whiskey advertised as single malt is produced from malted rye rather than malted barley.