Olababy Replacement Nipple Off-center nipple for a smooth milk flow and encourages comfortable upright feeding position. Breast-like nipple design creates a natural latch and encourages easy transition from breast to bottle Elevated wide dome creates a secure seal, reducing air intake and dribbles. Nipples are available to purchase in slow, medium, fast flow and X cut Dual Air Vent system reduces air ingestion Made with medical grade silicone and 100% BPA free