Give your baby the very best. Featuring a patented internal vent system, Dr. Brown's Natural Flow Options baby bottles are designed to allow your child to feed comfortably. This kit replaces worn or lost vent parts for Options 8 oz. bottles. Dr. Brown's Natural Flow Options Bottle Replacement Vent Kit replaces worn or lost parts For use with Dr. Brown's Options 8 oz. bottle Features a patented internal vent system Includes: 2 vent inserts 2 vent reservoirs Top-rack dishwasher safe Dr. Brown's Natural Flow Options bottles help reduce colic, spit-up, burping, and gas (sold separately) Made in USA SKU # 46382160