The NaturalFit® Advanced Feeding System is engineered to be responsive to the changing feeding styles of babies. Three distinct nipple shapes adapt to the specific needs of growing babies as the natural suck-swallow action develops. The Stage 1 nipple with its unique angle and wide, rounded base fulfills specific needs of the newborn. The angle of the nipple encourages proper positioning and neck support of baby for feeding. This angle also keeps the nipple full of milk, helping to reduce the chance of baby swallowing air.