Comotomo Silicone Replacement Nipples feature a wide-mound with built-in air-vents to help even the fussiest babies take a bottle. The naturally shaped design mimics breastfeeding to help make the breast to bottle (and back) transition seamless by mitigating nipple confusion issues. The built-in dual anti-colic vents help to reduce colic and ensure consistent milk flow every feeding. Comotomo nipple packs are replacements specifically designed for Comotomo Baby Bottles. BPA FreeMade with BPA-free materials.