The Pigeon Flexible Nipple LL, the perfect choice for a seamless transition between breast and bottle feeding. Backed by over 60 years of research on baby's natural suckling motion, our Flexible Slim Neck Nipple is so soft it flexes to the movements of babies' mouth and bends naturally to baby's mouth movement. The nursing bottle's Air Ventilation System (AVSTM) reduces intake of gas, a potential cause of colic. For 12+ months. Y-cut enables faster flow of milk. Upgrade to this size if baby is not satisfied with L size. BPA/BPS Free.