PIGEON Silicone Nipple was designed based on advanced nursing research and study to provide the best for mothers and babies. These are Super-Stretchable teats to encourage baby's natural suckling motion. Made from thick ultra-soft silicone material, the nipple has similar elasticity to that of a mother's actual breast. The dome-like shape makes baby's mouth open naturally, and supports its mouth softly and fitting its lips gently. All the nipples are Peristaltic Nipples and ensure minimum air intake smoothly into baby's stomach during feeding to avoid colic.