The Avent Anti-Colic Bottle SCF403/15 features a slow flow nipple that helps promote the health and comfort of your baby. It is proven to reduce colic and fussiness especially at night. The unique valve integrated into the nipple flexes of this Avent bottle allows air into the bottle, preventing vacuum build-up and preventing air into your baby’s tummy. The valve also flexes to their feeding rhythm so milk only flows at their pace to minimize overeating, spit-up, burping and gas. The extra-soft silicone nipple on this Anti Colic Baby Bottle is available in different flow rates for babies of all ages. It is easy to clean and this promotes good hygiene.