Clinically proven to reduce colic and discomfort We recommend you replace nipples every 3 months for hygiene reasons.Anti-colic valve integrated into the nipple vents air into the bottle and away from baby's tummy. Designed to reduce gas and fussiness Only 4 parts for quick and easy cleaning and simple assembly A range of flow rates are available for your growing baby. This bottle includes a 0Month+ Newborn nipple Trusted by millions of moms since 1984, Philips Avent is the #1 brand recommended by moms worldwide