Playtex VentAire Advanced Standard Baby Bottles are better for babies. A clinical study confirms that babies using Playtex VentAire Advanced Standard Baby Bottles had less gas spit-up colic and other discomforts than with other leading bottles. Unlike ordinary bottles VentAire Advanced keeps air at the back of the bottle as babies drink so virtually no air mixes with the milk and gets into babies tummies. The bottles reduce the negative effects of vacuum build-up so babies control the milk flow comfortably. The angled bottle design promotes the semi-upright feeding position recommended by pediatricians to help prevent ear infections.