Dr. Brown’s uniquely designed Natural Flow Options+ Wide-Neck Level 4 Nipple is a fast flow nipple, designed for babies who are more developed or prefer a quick flow. 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 Wide-Neck Level 4 Nipple gives baby vacuum-free feeding clinically proven to reduce colic, 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 Level 4 nipple is 9 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.Features: Suggested age range for the Level 4 nipple is 9 months+ Breast-like shape encourages proper latch for natural feeding experience Correctly contoured nipple shape and soft silicone give comfortable feeding experience and helps avoid nipple confusion Perfect for switching from breast to bottle and back again Fits Dr. Brown's Options+ Wide-Neck bottles (Sold Separately)