The Lansinoh mOmma NaturalWave Peristaltic Nipple is substantiated through over 50 years of research that shows that when baby"s use it, they are utilizing the same actions they use when nursing naturally. It is the ideal product for breastfeeding moms who will be apart from their babies, due to work or other reasons, so they can know that their baby will more easily go from breast to bottle and back to breast because this nipple minimizes the potential confusion or preference towards an artificial nipple that does not allow baby to engage the same natural-like actions. Allows baby to mimic natural sucking rhythm. BPA Free. AVS - Air Ventilation System reduces intake of gas, a potential cause of colic or spit up. 100% silicone is supersoft, flexible and long lasting.