This 2-pack of Dr. Brown's Y-Cut wide-neck replacement silicone nipples is designed exclusively for Dr. Brown's Natural Flow wide-neck baby bottles. The nipple's Y-shaped opening provides a faster flow than standard nipples, making it ideal for thicker liquids and babies 9 months and older. Made of super-soft, high-grade silicone, each nipple has a contoured, breast-like shape that encourages a proper latch and eases the transition between breast and bottle feeding. The wide-neck design has a broader profile for a more natural feel. Dishwasher safe (top rack only).