Together with the anti-colic internal vent system, Dr. Brown’s® bottle nipples provide a consistent flow that allows babies to feed at their own pace, while vacuum-free feeding helps support digestion for a more comfortable feed and a better night’s sleep, and the bottles are proven to help preserve bottle milk nutrients while reducing colic, spit-up, burping and gas, with soothing made easy thanks to the included Dr. Brown’s® HappyPaci™ made of 100% silicone and shaped like a bottle nipple for natural latching and increased acceptance, all components being dishwasher safe (top rack only) and sterilizer safe, BPA free, and including three 4 oz / 120 mL Options+™ Narrow Bottles along with one HappyPaci™ Pacifier