Introducing Dr. Brown's Options: The market's first convertible bottle that can be used with or without the vent system. It helps reduce feeding problems, helps digestion and helps preserve vitamins. Some moms and dads find removing the vent a convenient option as their baby's feeding becomes more developed. The nipple venting creates a paced flow, and provides a feeding experience similar to most nipple-vented bottles. Options bottles fit most breast pumps, and are BPA-free. The Power Of Choice. Two- 4 oz/120 ml bottles, Three- 8 oz/250 ml This innovative bottle effectively and efficiently covers all parents' needs. Brown's Options grows with the needs of your baby and offers healthy benefits whether your little one is experiencing feeding challenges or not. Options gives you the power of choice.