The Avent Bottle works with baby's natural feeding action so your baby controls milk flow, which can help reduce overeating and spit up. This helps develop a healthy feeding pattern. *1 m+. *Extra soft. *Slow 2 holes. *Reduces colic. *Less air in baby's tummy. *Anti-colic valve reduces colic. *Easy to combine breast and bottle feeding. *Clinically proven to reduce colic: *This bottle is made from polyether sulphone (PES) - a BPA-free material with a natural honey-colored tint.