Anti-colic x2 gives your baby more protection. The bottle has a colic valve to prevent colic, and the AirFree device effectively prevents air from entering the nipple. Even when held horizontally to feed your baby. It will help reduce the problem of swallowing air into the stomach while drinking milk that causes bloating, indigestion, gas in the stomach, and acid reflux. It is a feeding bottle that mothers around the world use, trust, and recommend.