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.Designed to mimic breastfeeding to reduce bottle rejection and nipple confusion.Built-in dual anti-colic vents provide consistent milk flow without the unwanted air-intake to prevent colic.Made with high quality, food contact grade silicone for safe feeding, free from chemicals such as BPA, PVC, and Phthalates.Truly wide-neck design makes it easy to clean the bottles by hand without a brush.Safe to clean in dishwashers (top rack), as well as microwave, steam, and electric sterilizers.