The nipple only releases milk when baby drinks \ \ the natural response nipple adapts to your baby's natural feeding rhythm, making it easier to combine breastfeeding and bottle feeding. The nipple has a unique hole that only releases milk when baby drinks. So when baby pauses to swallow and breathe, the milk flow is also interrupted. \ \ natural latch-on with a nipple shaped like a woman's breast \ \ the wide, soft and flexible nipple is specially designed to mimic the shape and feel of a woman's breast, making it easier for your baby to latch on and feel comfortable. \ \ specially designed to reduce colic and discomfort \ \ the anti-colic valve is specially designed to keep air out of baby's tummy during feeding, helping to reduce colic and discomfort. \ \ the non-drip nipple design helps prevent leaks and milk loss \ \ the nipple hole is specially designed to release milk only when baby drinks. So you can be sure that you won't have any milk loss whether at home or on the go. \ \ natural response nipples and bottles are bpa free* \ \ philips avent natural bottles and nipples are made of bpa free* material. \ \ choose the right milk flow for your baby \ \ every baby has their own rhythm when it comes to feeding and growing. we designed a range of flow rates so you can find the one that's perfect for your baby and personalize their bottle. all natural response nipples are made of soft silicone. \ \ be patient as your baby adjusts \ \ the new natural response bottles are different from free-flow bottles. Just like with breastfeeding, it may take a few tries to get it right. This is completely natural. \