The Philips Avent Anti-colic Teat Flow 1 is our slowest-flow teat, ideal for newborns and breastfed babies who are learning to drink from a bottle. The anti-colic valve integrated into the teat prevents air from entering your baby's tummy, thus reducing colic and discomfort. The valve flexes as baby feeds, allowing air to enter the bottle, preventing vacuum buildup and venting air into the back of the bottle. It keeps air away from baby's tummy, helping to reduce colic and discomfort. The nipple shape ensures safe sucking and the ribbed design helps prevent collapse for uninterrupted, comfortable feeding. The anti-colic teat is made of tasteless, odorless, soft silicone that resists discoloration and sticking and is BPA-free.Philips Avent anti-colic teats are available in different flow rates to keep up with your baby's growth.