Philips Avent BPA Free Natural Fast Flow Nipple Philips Avent Natural fast flow nipples are designed to help babies combine breast and bottle feeding. The nipple's wide shape is similar to the shape of a breast, and its soft, rounded nipple encourages natural latch on. A unique petal design increases flexibility and helps prevent nipple collapse while your baby feeds. Also, the advanced, twin anti-colic valves keep air in the bottle and out of babies' tummies, making feeding more comfortable. The nipples are made of soft, durable silicone. The fast flow rate is meant for babies who are at least six months old. The Philips Avent Advantage We know the tiny details can make a difference to you and your baby.