Nuk Fun Grips Spill Proof Cup Nuk Fun Grips Spill Proof Cup is an attractive sipper that changes its color whenever cold liquid is poured in. This cup is designed for a better grip and its lid is interchangeable to fit on other similar cups. Outer surface of the cup is textured to give it a neat appearance, while its special valve makes it spill-proof. Why You"ll Love It: Children will enjoy sipping from this cup as it changes color whenever cold liquid is poured in and reverses with the touch of a warm hand. Age: 12 months and up FeaturesCups change color when filled with cold liquid Patented valve makes them spill-proof Outer surface of the cup is textured for better grip and control Interchangeable lids can be used with other similar cups Safe for dishwasher cleaning