Comes in 4 colors, Anti-colic vent system, Decreases spit-up, burping, and gas,Shown to better preserve nutrients in breast milk and formula; Aids in digestion for good night’s sleep,Offers flow rate that supports breastfeeding; Soft silicone nipple helps breastfeeding baby naturally latch. Nipple Level: Level 1 - Slow Flow,Each nipple is engineered for consistent flow, so you and baby know what to expect,Fits most breast pumps,Dishwasher (top rack) and sterilizer safe