Includes three Wide-Neck 8-ounce Dr. Brown's Natural Flow baby bottles with Level-One nipples. Dr. Brown's Natural Flow baby bottle was invented by a doctor and tested on his own children when they were babies, so you can rest assured that this product is as safe as it is effective. This revolutionary baby bottle features a patented "no vacuum" design with an innovative design that reduces: Air bubbles in formula and milk. Colic. Burping. Spit-up. Gas. Fluid in the ear. Nipple collapse.