Add a pleasant twist to your morning routine with this glossy magic mug. It appears black when cold, but reveals a vibrant print when exposed to hot liquids. That makes this mug a wonderful gift for your family or friends. ? Ceramic ? Black glossy finish when cold ? Reveals the print when exposed to hot liquids ? Dimensions: height - 3.54'' (8.9 cm), diameter - 3.35" (8.5 cm) Note that in some instances the coating might not be 100% opaque and an outline of the design might peek through a little. You shouldn't put mugs in a microwave or dishwasher since it can damage the coating.