Dual Anti-Colic Vent, Air goes in, milk comes out to ensure ideal air circulation to reduce unwanted colic, spit up, burping and gas;Comotomo baby bottles are deisgned to most closely mimic breastfeeding to reduce bottle rejection and nipple confusion issues;Ultra wide-neck design allows easy cleaning by hand without a brush; Safe in microwave, boiling water, dishwashers and sterilizers;Nipple and body is made of 100% safe hygienic medical grade silicone;Safe: No BPA, PVC, Phthalates, Nitrosamine