MAM's nipples are designed to resemble a mother's nipple during feeding. To achieve this, MAM observed 16 infants breastfeeding using ultrasound technology. The result is a unique, flat shaped nipple that fits perfectly in baby's mouth and makes the switch back-and-forth between breast and bottle easy. All MAM products are made from BPA-free materials scientifically proven for maximum safety. These nipples fit all MAM bottles and are suitable for all breast milk and formula. The MAM nipple is available in five different flow rates: 0 (newborn), 1 - slow flow (0+ months), 2 - medium flow (2+ months), 3 - fast flow (4+ months) x - extra fast flow for thicker liquids (6+ months). ** Market Research 2009-2017, tested with 1,508 babies.