Nuby Flip-it cup with touch-flo valve promotes natural drinking action and healthy oral development. The valve opens with minimum pressure and doesn"t require constant sucking that can damage new teeth and soft palates. The flip it cover keeps the straw clean and hygienic.10 oz/ 300ml. Easy -Flo Straw, Step 3, 12 months +, Easy for little ones to get a firm grip, Perfect for on the go drinking, Hard, bite resistant straw, BPA FREE.