Dr. Brown’s Natural Flow Baby Bottle is award-winning clinically proven designed to reduce colic gas and discomfort. Crafted with a combination of high-quality polypropylene and soft 100% silicone these bottles feature an innovative internal vent system that helps reduce spit-up burping and gas while preserving the nutrients in breast milk and formula. The bottles come with a set of 3 Level 1 Silicone Nipples ideal for newborns and babies starting out with bottle feeding providing a gentle and consistent flow. Additionally 3 two-piece patented internal vents and cleaning brush. Each nipple is thoughtfully engineered to ensure a smooth predictable flow helping your baby latch naturally and comfortably just like breastfeeding. Safe convenient and versatile these bottles are top-rack dishwasher and sterilizer safe making cleanup a breeze. Theyre also BPA-free and designed to fit most breast pumps offering maximum convenience for busy parents.