The Pigeon Silicone Nipple is designed based on advanced lactation research and study to offer the best for moms and babies. These are the super stretchy nipples to encourage baby's movement for breastfeeding. Made of thick, ultra-soft silicone material, the nipple is flexible and similar to that of an actual mother's breast. Dome shape makes baby's mouth open naturally, softly support mouth and gently fit on the lips. All nipples ensure a minimum amount of air smoothly in the baby's stomach during feeding to avoid colic.