* Can Be Used With All Pura Bottles * One Two Pack Contains The Same Nipple Twice The Pura Kiki Silicone Cap Is Made Of Silicone And Comes In Four Different Sizes: Slow Flow: From 0 Month Medium Flow: From 3 Month Fast Flow / Y: From 6 Month Xl Sipper: 6 Month+ If It Should Happen With Your Nipple For Learning To Drink That Sucking Is Not Possible, The Nipple Keeps Pulling Itself Back Into The Bottle, No Liquid Comes Out Or Only With Great Effort, Then The Pressure Compensation Is Not Working. It Is Enough To Gently Rub The Fingertip Or Fingernail Over The 3 Valves Once, Then They Open And The Bottle Works Perfectly. 100% High Grade Medical Silicone Free From Bpa And Ea. Dishwasher Safe. Responsibly Made In China