Product Description: Introducing our Heat Change Mug! This 11oz ceramic mug magically changes color when filled with hot liquid, revealing a vibrant "Happy Birthday" design. Perfect for coffee or tea, this heat-sensitive mug adds a fun twist to your drinkware collection. It's an ideal gift for birthdays, bringing a delightful surprise with every sip. Enjoy your favorite beverages in style and watch the transformation happen right before your eyes!