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. It helps colicky babies settle down/sleep and reduces colic, spit-up, burping and gas. This also helps to prevent fluid in the ear/no vacuum. It is easy to clean, and dishwasher safe. The two replacement silicone nipples, exclusively for Dr. Brown's Natural Flow Standard baby bottles. Ideal for feeding premature babies. Now you can just press a button to release the perfect amount of soap. The textured scrubbing bristles reach even the hardest-to-clean areas with ease, so your bottles will always be sparkling clean. The sturdy suction base grips tightly to keep brush in an upright position, away from germs and ready for one-handed cleaning.