Nuby’s FlipNSip cup is great for at home and on-the-go sipping. Nuby has designed the FlipNSip cup with a pressure-sensitive Touch-Flo valve to help prevent drips and spills. The Touch-Flo valve opens when children sip from the cup. When not sipping from the straw the valve closes ensuring a leak-resistant cup. The cup's Flip-it top tucks the silicone straw out of the way when closed keeping it clean. Parent s can have confidence this product will last because the cup base is made of durable break-resistant Tritan from Eastman. Stay spill-free and secure in your decision to take the FlipNSip cup on little adventures.