Lansinoh Anti Colic Baby Bottles with NaturalWave teats are designed to reduce nipple confusion and make it easy to switch between breast and bottle feeding. Each bottle comes with a medium flow teat and a stackable lid, perfect for storing breast milk in the fridge or freezer, and later for snacks from 6+ months. The innovative Air Ventilation System helps reduce air intake, a potential cause of colic and spit up. These bottles are BPA and BPS free, and connect directly to all Lansinoh breast pumps for convenient pumping and feeding.