Unique valve on the teat flexes to your baby's feeding rhythm. Milk will only flow at the pace chosen by your baby to minimise overeating and spit-up, burping and gas Sleep and nutrition are vital to your baby's health and happiness. A randomised clinical trial was carried out to see whether infant baby bottle design affects "infant behaviour". The Philips Avent Classic baby bottle was shown to significantly reduce fussing by approximately 28 minutes a day as compared to the comparator bottle (46 min vs. 74 min, p=0.05) This was especially true at night. As your baby feeds, the unique valve on the teat flexes to allow air into the bottle instead of your babys tummy. This teat is made from silicone - a BPA-free material (Following EU directive 2011/8/EU) With the Philips Avent Classic+ teat, your baby controls milk flow, which can help reduce overeating and spit-up.The unique valve flexes to allow air into the bottle, promoting healthy, active feeding and reducing fussing and colic.