Dr. Brown's Natural Flow Preemie Standard Nipple is ideal for feeding premature babies. Preemie Flow design limits the flow of milk and formula so babies can feed at the pace that's right for them. Made of super-soft, high-grade silicone and exclusively for Dr. Brown's Natural Flow Standard baby bottles, these nipples are BPA fre and dishwasher safe. Dr. Brown's Natural Flow Preemie Standard Nipple is ideal for feeding premature babies.