Natural Response Nipple: The bottle comes with the Natural Response nipple, which is designed to support the baby's unique suck, swallow, and breathe rhythm. The nipple has a unique opening that releases milk only when the baby actively drinks, mimicking the flow of breastfeeding. AirFree Vent: The bottle is equipped with an AirFree vent, which is designed to keep air away from the baby's tummy during feeding. This feature provides extra protection against colic, gas, and reflux, ensuring a comfortable feeding experience for the baby. Upright Feeding: The AirFree vent also allows for upright feeding, which can further reduce the risk of colic and discomfort for the baby. Ergonomic Bottle Design: The bottle features an ergonomic design that is easy to grip at any angle, providing maximum comfort for both the baby and the caregiver during feeding sessions. Overall, the Avent Natural Response Feeding Bottle with AirFree Vent offers a combination of comfort and functionality, making it an excellent choice for parents looking to provide calm and comfortable feeds for their infants while minimizing the risk of common feeding issues such as colic and gas. (description exceeds maximum possible length)