Natural latch on: The Philips Avent baby bottle nipple helps the baby to latch on and feed comfortably Works like the breast: The teat releases milk when baby actively drinks, this is different from the traditional free-flow teats. As with breastfeeding, it can take time for a baby to get used to this. AirFree vent: This Avent Bottle prevents air from getting into your little one's tummy whilst feeding upright. Right nipple flow: Find your baby's perfect flow rate and personalise your Avent bottle No-drip nipple: The bottle-feeding nipple only opens to release milk when the baby is feeding.