The Philips Avent Anti-colic nipple Flow 2 is great for babies 1 month and older and breastfed babies learning to drink from a bottle. The anti-colic valve integrated into the nipple is designed to keep air away from your baby's tummy to reduce colic and discomfort. As your baby feeds, the valve flexes to allow air into the bottle to prevent vacuum buildup and vents it towards the back of the bottle. The nipple shape allows for a secure latch and the ribbed design helps prevent collapse for uninterrupted, comfortable feeding. The anti-colic nipple is made of flavorless, odorless, soft, BPA-free silicone that resists discoloring and stickiness. Philips Avent bottle nipples are available in different flow rates to keep up with your baby’s growth. We recommend replacing nipples every 3 months for hygiene reasons. Use Philips Avent Anti-colic bottles only with Philips Avent Anti-colic nipples.