Description : SCF635 Less Air, Less Discomfort 2 Variable Flow Silicone Nipples 2 For Babies 3 Months Over 3 Reduces Colic 4 Ideal for Thicker Feeds 5 BPA Free Variable flow - for thicker liquids. Adjust flow rate by simply turning the bottle. Soft silicon nipple with a built in valve. Use only with Philips Avent classic feeding bottle. Instructions included.