Details: Philips Avent Natural Variable Flow Nipple features a slot hole design, allowing you to change the flow of milk, provides an extra fast flow and accommodates thicker liquids. Simply turn the bottle to line up the I, II or III marking with your baby s nose to choose between slow, medium and fast flow. These nipples are made of soft, durable silicone, which is odorless and flavorless. The nipples can be sterilized in any Philips Avent steam sterilizer, boiled for five minutes, or washed in the dishwasher. The wide breast-shape nipple promotes natural latch-on so you can easily combine breastfeeding and bottle feeding. Our flexible nipple design combined with the comfort petals allow for a natural movement while baby feeds. Unique Air flex vent technology is integrated into the nipple and are designed to reduce colic and discomfort by venting air away from your baby s tummy. For use with Philips Avent Natural bottles. SCF655 43. We recommend to use this nipple for thicker liquids such as AR (thickened) milk, milk mixed with baby rice, milk mixed with baby food, soup.