Our anti-colic valve is intended to fend off air from your child's stomach to lessen colic and uneasiness. As your child bolsters, the valve coordinated into the nipple flexes to enable air into the bottle to avert vacuum and vents it towards the back of the bottle. It keeps air in the jug and far from child's belly to help diminish colic and distress. Philip Avent bottle lessens complaining. Infants fed with Philips Avent Anti-colic bottles experienced 60% less whining during the evening, than babies bolstered with a contender's anti-colic bottle. The nipple shape permits secure lock and the ribbed surface aides averts nipple collapse for continuous, happy nourishing.