NUK Perfect Match Slow Flow Nipples are designed to offer a familiar feel and support a natural transition between breast and bottle. Their soft, flexible, skin-like silicone adapts to baby’s natural way of feeding, while the wide lip rest encourages an instinctive latch. The anti-colic air system helps reduce swallowed air for calmer feeds.-Soft, flexible, skin-like silicone adapts to baby’s natural way of feeding