They Are Designed To Follow The Development Of The Baby'S Mouth And The Way He Eats During The First Months. Silicone Teats That Resemble The Feel And Shape Of The Mother'S Breast. Equipped With An Anti-Colic Valve That Regulates The Flow Of Air Into The Bottle Avoiding The Risk Of Colic And Regurgitation. Ideal For Older Children And Has A Slightly Rounded Base And Elastic Teat To Favor Natural Sucking. Made Of Extra Soft Silicone.