The Philips Avent Natural 2.0 Teat Is Easy To Combine Breast And Bottle Feeding. Ultra-Soft Teat Mimics The Feel Of The Breast,Natural Latch On Due To The Wide Breast Shaped Nipple. A More Comfortable And Contented Feed For Baby,Advanced Anti-Colic System With Innovative Twin Valve,Unique Comfort Petals With Spiral Design For An Extra Soft And Flexible Nipple. Air Goes Into The Bottle, Not Baby'S Tummy