Convertible Bottle: This bottle is the market's first convertible bottle, designed to be used with or without the vent system. The vent system is recommended to experience all the health benefits of the bottle, including reducing feeding problems, aiding digestion, and preserving vitamins. Two-Piece Internal Vent System: Dr. Brown's patented two-piece internal vent system is designed to provide vacuum-free feeding, known as positive-pressure flow, similar to breastfeeding. As the baby feeds, air is channeled from the teat collar through the vent system, bypassing the breast milk or formula, reducing the ingestion of air bubbles and minimizing oxidation of nutrients. Paced Flow: The nipple venting creates a paced flow, offering a feeding experience similar to most nipple-vented bottles. This helps babies feed more comfortably, reducing feeding problems like colic, burping, and wind. Compatibility: Options bottles fit most breast pumps, providing convenience for pumping and feeding. BPA-Free: The bottle is free from harmful BPA (bisphenol A), ensuring safety for your baby. Health Benefits: University studies have shown that Dr. Brown's fully vented bottles help maintain levels of important nutrients like vitamins C, A, and E during feeding. The vent system minimizes oxidation of breast milk and formula, helping to maintain essential nutrients. Positive-Pressure Feeding: The fully vented bottle design provides vacuum-free feeding, promoting a feeding experience similar to breastfeeding. The Dr. Brown's Options Anti-Colic Wide Neck Feeding Bottle 270ml 3 Pack offers parents the flexibility to choose the feeding option that best suits their baby's needs, while also providing health benefits and comfort during feeding.