Closer to Natural Breastfeeding: Promotes more natural breathing, easy switching between breast & bottle and air free feeding to help reduce colic. Simulates same suck, swallow and breathe patterns as breastfeeding. As baby feeds, the soft disposable liner inside the bottle gently collapses (just like the breast does naturally when breastfeeding) to prevent air from mixing with the milk and getting into baby's tummy. , , Convenient for on the go: Our pre-formed, pre-sterilized liners are disposable providing you with a fresh, clean bottle anytime and anywhere. Air-Free Feeding to Help Reduce Colic: Unique anti-colic liner gently collapses as baby feeds, preventing air bubbles from mixing with milk and getting into baby's tummy. Less air bubbles means less gas, colic and discomfort.