Designed for Preemies & NewbornsClinically Proven to Reduce Colic, Spit-Up, Burping, and Gas 1 Pediatrician Recommended Baby Bottle In The U.SBPA FreeNarrow Fits Most Breast PumpsHelps Reduce Feeding ProblemsProven to Help Preserve Bottle Milk Nutrients*Vacuum-Free Feeding helps DigestionFully-Vented Bottle DesignInternal Vent System and Silicone Nipple Work Together *Per a university study. Contents 2 - 2 oz / 60 ml baby bottles 2 - Preemie Flow™ silicone nipples1 - Cleaning brush Instructions Internal Vent System Air enters the bottle collar and routes directly through the internal vent system.The air channels through the vent tube, bypassing the milk, to the end of the bottle.The vent prevents aeration of the milk, vacuum pressure and nipple collapse.Baby feeds comfortably while milk flows freely, like breastfeeding. The Dr. Brown's® vent system reduces air bubble oxidation to help preserve bottle milk nutrients. Our bottle works best with the vent system Clinically proven to reduce colicProven to help preserve vitaminsAids in digestion for a better night's sleepFlow rate supports breastfeeding