Back To The Future Retro TV Heat Changing 3D Mug Official Merchandise BNIB New. Take a trip back to the 1980s with the Back To The Future TV Heat Change Mug. Designed in the shape of an old TV with a screen which will change when heated. These special heat-changing mugs are perfect for birthday & Christmas gifts for any fans of the Back To The Future movies. 500ml/17oz ceramic mug. Add hot liquid to reveal the hidden design. Ideal gift for birthdays & Christmas. Officially licenced product Supplied in a cardboard gift box H x 10 W x 15cm approx. Not suitable for dishwasher or microwave use. Thanks for looking!