Dewar's 21 Year Old Double Double Scotch Whisky is a premium aged Scotch whisky. The "Double Double" refers to the double aging process the whisky undergoes, which involves aging the spirit in two types of oak casks. This process is said to give the whisky a rich, smooth flavor profile with notes of caramel, honey, and fruit. The 21-year aging period allows for additional time for the flavors to develop and mature. The 375ml bottle size is a smaller, travel-friendly option for those looking to enjoy a premium aged Scotch whisky.