The Nuby No Spill Insulated Soft Sipper with its colorful two-in-one cup design keeps liquid fresh and cool. This cup features a Soft Sipper spout which is gentle to child’s tender gums and emerging teeth. It is covered by an easy-to-use flip top cap. This uniquely designed feature protects the sipper spout from contamination when not in use. Great for travel and short trips. Flip cap keeps sipper sanitary and clean. When child is ready to use the cup, the top cap simply 'flips' back and rests in the lid of the cup. The sipper features a dual-flo valve system engineered to help protect against spills or leaks. Liquids pass through spout only when your child sips. (You control the flow by reversing the valve).