Philips AventClassic bottle is compatible with the overall range of Philips Avent, excluding Natural bottles and cup handles. Classic bottles are advised to be used with the Classic feeding nipples ; The unique valve on the nipple activates smooth baby feeding. The flow of the milk is at a constant pace which reduces gas, overeating and spit-ups ; Proper sleep and nutrition are important for the health and happiness of a baby. A clinical trial was carried out to see whether the ‘infant behavior’ is affected by the baby bottle design. The Classic baby bottles significantly reduce baby fussing by approximately 28 minutes. This was especially effective during night time.