Lansinoh Backed by more than 50 years of research, the NaturalWave Nipple enables baby to engage in the natural sucking motion learned at the breast, known as Peristaltic Motion. This is why our Nipple is clinically proven to reduce artificial nipple preference in established breastfed babies, making it easier for baby to go from breast to bottle and back to breast. Available in slow, medium and fast flow. Breastfed babies feed using peristaltic tongue motion, a wavelike action that extracts milk. Our 100% silicone nipple is made from the softest, most flexible silicone available, enabling baby to replicate this natural feeding action. Our Air Ventilation System (AVSTM) is designed right into the nipple, reducing babys intake of gas, which is a potential cause of colic and spit up.