A Gentle Squeeze makes all the difference... The SoftFlex™ Silicone Nurser features a revolutionary new soft air™ silicone base. Made from 100% BPA free silicone, the soft air™ silicone base allows the parent to assist with feeding by giving the bottle a gentle squeeze. It also features the new Nûby™ SoftFlex™ Breast Size Nipple which closely mimics nature. It has the natural shape, feel, and function of a mother’s breast which helps to ease the transition from breastfeeding to bottle feeding. It also features superior valves in the base of the nipple to help prevent colic, and soft nubs on the surface to massage baby’s gums. * Fully interchangeable with the SoftFlex™ Natural system.