Dr. Brown’s Natural Flow® Preemie Flow™ Nipple is the slowest flow, sized just right for premature babies, newborns, or babies experiencing feeding difficulties. Preemie Flow™ Nipple, together with Dr. Brown’s® Anti-Colic internal vent system, is clinically proven to reduce colic. Dr. Brown’s® bottle and nipple provide a more comfortable feeding experience for baby by decreasing spit-up, burping and gas. This vacuum-free feeding is closest to breastfeeding and Dr. Brown’s® Preemie Flow™ Nipples provide a consistent flow so baby can feed at their own pace. The breast-like nipple shape encourages a proper latch for a more natural bottle feeding experience and eases the transition from breast to bottle and back again. The Preemie Flow™ Nipple and Anti-Colic vent system is proven to help preserve bottle milk nutrients and aid in digestion for a better night’s sleep. Made of super-soft, 100% silicone, the Preemie Flow™ Nipple fits all Dr. Brown’s® narrow bottles. Safe for use in dishwasher (top rack only), electric and microwave sterilizers or boiling water. BPA free.