Keep air in the bottle - not your baby's sensitive tummy! The Avent Anti-colic Bottle Slow Flow Nipple, BPA Free is a slow-flow nipple that offers an anti-colic valve, a feature that reduces fussing and colic. The unique valve flexes to your baby's feeding rhythm so milk will flow at the pace chosen by your baby for more comfort. These soft, rounded Anti-colic bottle nipples are made of durable, dishwasher-safe silicone, which is flavorless and odorless. Two-Hole Nipple with Slow Flow Rate The Slow Flow nipple has two holes and is designed for babies who are at least one month old and for breastfed babies of all ages. As with breastfeeding, babies can control the flow of milk themselves, which reduces overeating and spit-up. What's in the Box Two Philips Avent Anti-colic slow flow nipples. -Nipple features 2 holes ideal for babies at least 1 month old and breastfed babies of all ages -Clinically proven to reduce colic -Compatible with all Philips Avent Classic bottles -BPA-Free -Dishwasher safe