These are cold-sensitive color changing cups. When you add any cold drinks, such as iced water, ice coffee, etc., the color of the cup will change magically. After the cup has warmed, the cup will return to its original appearance. In winter, the cup may change to dark color itself due to low temperature. Various colors increase the sense of style and make your drinking time brighterBPA Free Plastic Material: These tumblers with straw is made of Food-Grade PP and BPA free. The reusable cups with lids and straws are very safe and healthy for kids and adultsPerfect for Small Hands: Our Cups with straws and lids are the most comfortable size to hold. Not only do smoothie cups with lids feel good for kids, they are also ideal for adults.Spill Proof: The kids tumbler with lid and straw attached is splash-proof. The color changing cups for kids and adults are sturdy and won't leak easily. The snug snap-on lids fit tumbler cup set securely to prevent spillPackage included: 1 x Cup with strawsNote:Please allow 1-2 cm difference due to manual measurement.Besides different computers display colours differently, the colour of the actual item may vary slightly from the below images, thanks for your understanding(1 inch = 2.54 cm)