Natural flow. Clinically proven to reduce colic. Spit-up, burping, and gas. New breast-like nipple for more natural feeding. Use with or without vent. Designed to grow with baby. Number 1 Pediatrician Recommended baby bottle in the U.S. Dr Brown’s by Handi Craft. 2x9 oz. 270 ml. Happy Feeling. Internal Vent System: (1) Air enters the bottle collar and routes directly through the internal vent system. (2) The air channels through the vent tube, bypassing the milk, to the end of the bottle. (3) The vent prevents aeration of the milk, vacuum pressure and nipple collapse. (4) Baby feeds comfortably while milk flows freely, like breastfeeding. See how it works at drbrownsbaby.com. The Dr. Brown's vent system reduces air bubble oxidation to help preserve bottle milk nutrients. Vitamin C in Breastmilk. Options use with or without vent. Our bottle works with the vent system. Clinically proven to reduce colic; Proven to help preserve vitamins; Aids in digestion for a better night’s sleep; Flow rate supports breastfeeding. But it’s great to have options when baby’s feeding develops. Remove vent- no need to introduce a different bottle; Feeding experience similar to most nipple-vented bottles. Helps reduce feeding problems. Our bottles are known for reducing colic, spit-up, burping and gas; Proven to help preserve bottle milk nutrients (Per a university study. Learn more at drbrownsbaby.com/nutrient-study. 0m+ premie flow; 0m+ level 1; 3m+ level 2; 6m+ level 3; 9m+ level 4; 9m+ Y-cut. Choose the right nipple. Made of super-soft, high-grade silicone, each nipple level provides a different flow rate. Contents: 2 - 9 oz/270 ml Wide-Neck baby bottle; 2 - level 1 silicone nipples; 1 - Cleaning brush instructions. Complies with EN 14350. drbrownsbaby.com. www.drbrowns.co.uk. Learn more at nutrientstudy.com. This package is manufactured with 100% recycled paperboard. BPA free. Made in the USA.