Convertible Bottle: The market's first convertible bottle that can be used with or without the vent system, allowing parents to customize the feeding experience based on their baby's needs and feeding preferences. Vent System: The patented two-piece internal vent system is designed to reduce feeding problems, aid digestion, and preserve essential nutrients in breast milk or formula. It eliminates negative pressure and air bubbles, reducing the risk of colic, burping, and wind. Paced Flow: The nipple venting creates a paced flow, simulating a natural breastfeeding experience and providing a comfortable feeding for the baby. Compatible with Breast Pumps: The Options bottles fit most breast pumps, offering convenience for breastfeeding mothers who need to pump and store breast milk. BPA-Free: Made from BPA-free materials, ensuring the safety of your baby during feeding. Grows with Baby: The vent system is designed to grow with your baby, providing health benefits and a positive feeding experience as your little one develops. Preserves Nutrients: University studies have shown that Dr. Brown's fully vented bottles help maintain levels of important nutrients like vitamins C, A, and E in breast milk and formula, thanks to the minimized oxidation provided by the vent system. Overall, the Dr. Brown's Options Anti-Colic Wide Neck Feeding Bottle offers a comprehensive solution for parents seeking to provide a comfortable and healthy feeding experience for their baby, while also accommodating the evolving needs of their growing child.