The Dr. Brown’s Natural Flow® bottle is fully vented to create a positive-pressure flow for vacuum-free feeding. Clinically proven to reduce windy colic due to its unique 100% vacuum-free vent system, that as baby feeds and fluid enters the infant’s mouth, the air is channeled back from the infant through the teat and the vent system bypassing the breastmilk or formula during feeding. This system prevents the negative effects of a vacuum, allowing babies to feed more comfortably and eliminating discomfort from ingesting air, thereby reducing the symptoms of colic, spit-up, burping and gas. Dr Brown’s Options+ bottles offer an easy and comfortable way to feed your little-one, adapting to their needs as they grow. With the unique design, this bottle can be used with or without the removable internal vent system, transforming it into a teat-vented bottle for more convenience.