Dr. Brown s bottles feature a patented internal vent which reduces air bubbles and helps to prevent fluid in your baby s ears. Bottles are compatible with breast feeding, and they help colicky babies settle down and sleep. They also reduce colic, spit-up, burping and gas and are easy to clean. These are dishwasher safe and include one 8 oz. natural flow standard bottle. Polypropylene bottles are BPA Free.