The Anti-Colic Valve Flexes To Allow Air Into The Bottle, Reducing Colic. The Soft, Naturally Shaped Teat Makes It Easier To Combine Breast And Bottle Feeding. Bottle Is Made From Pes, A Bpa-Free Material With A Natural Honey-Colored Tint. Shaped For Stability And Comfort, Its Waited Shape Is Easier To Hold And Its Wide-Neck Design Makes Filling And Cleaning Easy. Clear Markings On The Bottle Ensure Accurate Measurement And Make It Easier To Determine How Much Baby Has Been Fed. The Dome Cap Seals The Teat Securely, To Ensure Leak proof Mixing And Travel Without The Need For Separate Sealing Discs.