Description About the Harry Potter Hogwarts magic mug . Because of its heat-sensitive coating, which reacts to the heat, the mug changes its color from black to white . When the Harry Potter Hogwarts magic mug is cold it is black and the image is slightly noticeable. But when filling it with hot drinks – tea, coffee, milk or water, its color becomes lighter and the printed image gradually appears. The mug is a delightful, original and impressive gift for your family or colleagues. Artwork is slightly visible when cold
