A distinctive nipple features an air valve at the base, promoting a venting process that allows for a seamless liquid flow and reduces the risk of nipple collapse, colic, spit up, burping, and gas. Specially designed for Pur Advanced Feeding Bottles. It mimics the experience of breastfeeding and aids in the formation of a baby's palate by enhancing suction. Constructed with premium medical grade silicone, it is safe from volatile and nitrosamine substances. It is odorless, tasteless, and guaranteed to last. Plus, it is BPA free.