These essential Comotomo Baby Bottles are created to simulate breastfeeding and to reduce the occurrence of bottle rejection in babies and nipple issues for picky infants. The extra-wide neck permits easy cleaning without the need for a bottle brush. Heat-safe – great to use in microwaves, dishwashers, boiling water and more. Made from 100 percent safe, sterile, medical-grade silicone, these Breastfeeding Simulating Baby Bottles are feature dual, anti-colic vents to prevent air-intake and reduces the occurrence of colic in babies.