The Starbucks Harry Potter Color Changing Mug (set of 4 pcs with one Sorting Hat Lid) is a unique and collectible set featuring a multi-color design that changes based on the temperature of the liquid in the mug. This set of 4 12oz mug comes with a Sorting Hat Lid, adding an extra touch of magic to your coffee or tea experience. Officially licensed by Starbucks, this original product is perfect for fans of both coffee and Harry Potter.