"Our most breast-like bottle, ever. Makes switching from breast to bottle and back again, easy. Soft, silicone nipple, that flexes and stretches like a breast.Anti-colic valve, to keep gas away from baby’s tummy.Speedy self-sterilizing, in just three minutes in the microwave.* 100% leakproof with the lid (even when upside down).It’s also BPA free *Based on placing one bottle in microwaves from 700-1000w."