Dr. Brown’s Natural Flow® Anti-Colic Preemie Baby Bottle is sized just right for premature babies. The small 2oz/60mL bottles feature our Preemie Flow™ nipples, offering our slowest flow rate for babies who are premature or experiencing feeding difficulties. The anti-colic internal vent system is clinically proven to reduce colic. Dr. Brown’s bottles 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 silicone nipples provide a consistent flow so baby can feed at their own pace.