Bottom vented, one-way PetalÃ'® valve offers consistent air flow reducing possibility of colic;Supports transition from Mother's breast to bottle;Soft Medical grade Silicone Nipple that is ideal in shape and size; Bottle disassembles in 3 convenient pieces for ease of cleaning;Dishwasher safe (top rack only); BPA Free;Designed for 9+ months of age; 4 Pack