Cardhu is the Speyside home of Johnnie Walker, and the distillery contributes much of its production to the world-famous blend. So much so in fact that the Cardhu brand was turned into a vatted "pure malt" for a brief period in 2002 to ease pressure on its stock, but quickly reverted back to a single malt in 2004 following widespread criticism. The incident saw the rewriting of the rulebook for single malt whisky, and the birth of the term "blended malt," adding some infamy to the Cardhu history books in the process.
This is a 1980s bottling of the 12 year old age-statement. Cardhu was one of a number of DCL distilleries that were licensed to John Walker & Sons in the 1980s due to its importance to their blends, along with high profile names like Talisker and Mortlach. This was common practice at the time, and continued until the company's subsequent iteration, United Distillers, began to restructure by withradwing these licenses and reclaiming control over the distribution of its single malt portfolio.