Harry Potter Ravenclaw Logo Custom Morphing Coffee Mug Tea Cup 11 OZ Office Home Cup (Printed on two sides) Material: 100% ceramic Come in 11oz sizes with a large handle. Perfect for coffee, tea, milk, hot cocoa, soup and more. Morphing:Just plain black in color when it's cold,mug will turn white and reveal Design only when filled with a hot beverage Treat yourself or give as a gift to someone special.