Introducing Dr Brown's Options: The market's first convertible bottle that can be used with or without the vent system. The new vent system is designed to grow with baby, and we recommend using this system to experience all the health benefits of our bottle. 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 and made in the USA. The anti-colic internal vent system features an enhanced design to improve an already innovative feeding experience: - Clinically proven to reduce colic - Decreases spit-up, burping, and gas - Shown to better preserve nutrients in breast milk and formula - Aids in digestion for a good night's sleep - Offers a flow rate that supports breastfeeding. Pack contains: 1 x 9 oz/270 ml bottle 1 x Butterfly Pacifier 1 x Pacifier Clip 1 x Cleaning Brush