Get ready for the countdown with this Thunderbirds heat changing mug. Cold, the mug displays a navy blue background with the iconic Thunderbirds logo in red, beneath that are the numbers 5, 4, 3, 2 and 1, providing a sneak peek of the awesome Thunderbirds design that lies beneath! When hot liquid is poured in, the design transforms to reveal artwork of all five famous Thunderbirds machines in action against sunny skies. Once the drink is finish the mug returns to its original state as it cools. An essential for any Thunderbirds fan or display.