Dr. Brown's Natural Flow® Original Bottle is the original anti-colic bottle with a unique internal vent system that offers vacuum-free feeding. Each nipple is specially engineered to offer the same consistent, natural flow, so you and baby know what to expect. The soft silicone nipple helps baby naturally latch while the anti-colic vent system lets baby feed without fuss. Together, they offer a reliable and trusted bottle feeding experience that makes Dr. Brown's the #1 pediatrician recommended bottle in the U.S. Plus, the anti-colic internal vent system is clinically proven to reduce colic, decreases spit-up, burping, and gas, better preserves nutrients in breast milk and formula, aids in digestion for a good night's sleep, and offers a flow rate that supports breastfeeding. Dishwasher (top rack) and sterilizer safe. BPA free. 0m+.