See the most famous School of Witchcraft and Wizardry on this Harry Potter heatchange mug by GB Eye! Discover our range of heat change mugs!!!!! Every morning, you can see your mug change dramatically when you pour your hot chocolate, your tea or your coffee. Details: – Design changes when you pour hot liquid. – Size: 320ml. – Material: ceramic. – Not suitable with microwave and dishwasher. – Packaging: closed box.