This colour changing tumbler is a 20oz double wall tumbler that allows for a unique experience. The tumbler is cleverly designed to change colours into a gradient rainbow when pouring or holding cold liquid in it, which adds an exciting and fun element to drinking your favourite beverages. The double wall construction of the tumbler ensures that your drinks remain cold for a longer period of time, making it perfect for hot summer days. Overall, this colour changing tumbler is a great investment for anyone who wants to add a little bit of magic and excitement to their daily routine. Whether you're enjoying a morning smoothie or showing off your tumbler at a party, this product is sure to make a lasting impression.