mOmma by Lansinoh Nipples - Slow FlowNaturalWaveTM Peristaltic Nipple Features:• Patented, based on over 50 years of research• Allows baby to mimic natural sucking rhythm• Promotes oral, facial, and jaw development• AVSTM Air Ventilation System reduces intake of gas, a potential cause of colic or spit up• One piece, hassle-free design• 100% silicone is supersoft, flexible and long lasting• Available in slow, medium or fast flow to meet your baby's changing needs• BPA Free