Our unique AirFree vent is designed to help your baby swallow less air as they drink by keeping the nipple full of milk during feeding. Reducing the amount of air your baby ingests helps with common feeding issues such as colic, reflux & gas. Features: -Clinically proven to reduce colic and fussing2 -Nipple stays full of milk, not air -Helps baby swallow less air with AirFree vent -Bottle  4oz / 125ml