Breastflow's patented 2-in-1 nipple lets your baby control the flow of breast milk or formula as naturally as breastfeeding. By using both suction and compression motions, your baby is able to regulate the flow of milk unlike any other bottle. Plus, Breastflow is designed to help prevent colic. Moms who participated in an independent in-home bottle feeding research study said their babies experienced reduced colic symptoms such as less gas, spit-up or fussiness when using Breastflow. Whether you choose to feed your baby breast milk or formula, Breastflow provides a unique bottle feeding experience unlike any other for a satisfied baby and happy mom.