Anticolic design VentAire bottles are specially designed to prevent colic by reducing air ingestion The patented anticolic bottom vent keeps air at the back of the bottle as baby drinks so no air mixes with the milk Angled design The bottles ergonomic angled design promotes semiupright feeding which is recommended by pediatricians to help prevent ear infections Doctor recommended Features The bottom vent for airfree FEEDING and the angled design for more upright feeding are doctor recommended TO help reduce reflux colic gas burping and spit up Nipple designed to feel like mom Designed to be most like mom The wide shape Naturalatch silicone nipple encourages proper latching promotes healthy feeding and allows you to easily switch between breast and bottle feeding Easy to clean reassemble VentAire bottles are designed with fewer parts making cleaning and reassembly quick and easy