The NUK Smooth Flow Pro Anti-Colic baby bottle is equipped with an anti-colic ventilation system which has been proven to reduce symptoms of infant colic such as gas and reflux. Advanced ventilation system minimizes air bubbles in milk , so the child swallows less air reducing regurgitation and belching. The unique design of the newborn bottle nipple allows the baby to control the flow of milk through suction force providing comfortable feeding without colic.