The Medela Special Needs Feeder is designed for babies with cleft lip and palate and babies with neurological disorders. The one-way valve membrane between bottle and teat means no air can enter the teat. In addition to this, the Special Needs Feeder has a slit-valve which enables you to regulate the flow of breastmilk, by simply changing the position of the teat in your baby's mouth. Even if your baby only suckles gently, he is able to activate the breastmilk flow.