Philips Avent Natural Response Bottle With Airfree Vent 125ml Die 50 besten Internate in England: Was macht Sie aus?. Natural Response nipple: The unique Philips Avent bottle nipple opening only releases milk when the baby actively drinks. 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. No drip nipple: The bottle feeding nipple only opens to release milk when the baby is feeding. Comes with Flow 2 Teat suitable for 0m+ BPA Free