Dr. Brown's Natural Flow Options+ Preemie Flow Wide-Neck Nipple is our slowest-flow nipple, great for premature and breastfed newborns. The breast-like shape encourages a proper latch for a more natural bottle feeding experience. Designed alongside medical professionals, the correctly contoured nipple shape and high-grade, soft silicone offer a more comfortable feeding experience and help to avoid nipple confusion. , , Perfect for switching from breast to bottle and back again! Together with the anti-colic internal vent system, the Preemie Flow Wide-Neck Nipple gives baby vacuum-free feeding that is clinically proven to reduce colic, decreases spit-up, burping, and gas, better preserves nutrients, and aids in digestion for a good night's sleep. While our bottle works best with the vent system, it's great to have options when baby's feeding develops. Just remove the vent and the feeding experience is similar to most nipple-vented bottles. The suggested age range for the Preemie Nipple is 0 months+ but baby's preferred flow rate may vary. Fits Dr. Brown's Options+ Wide-Neck bottles. Dishwasher (top rack) and sterilizer safe. BPA free.