Rabbit Hole The King Cask Strength - This single barrel expression has been gracefully aged for 4 years and 2 months in hand-selected barrels and only harvested once the mingling of whiskey and wood yielded an equisite spirit like no other. At full cask strength, with nothing added and nothing taken away, this one-of-a-kind whiskey is a sensory experience to be cherished. 105 Proof, 52.5% ABV.