NUK bottles now feature improved Perfect Fit nipple, which provide a natural way to bottle feed your growing baby. The Perfect Fit unique nipple shape is inspired by Mom's nipple which changes shape during breastfeeding and it's the same shape as the NUK Perfect Fit nipple. It provides the perfect fit in baby's mouth just like Mom, so you know that your baby will love the NUK bottles. Perfect Fit nipples feature Soft Zone and Anti-Colic Air System that helps reduce colic, gas and spit-up. 1-piece vent is integrated into the nipple so there are no extra parts to clean. Soft Zone provides greater comfort as soft satiny finish conforms to baby's palate. Perfect Fit nipples are optimally sized to support baby's growing mouth and appetite, available in 2 nipple sizes and 3 flow rates. The wide bottles are easy to use, clean, and assemble and are dishwasher safe. For best results when feeding, make sure that the NUK Anti-Colic Air System symbol is under baby's nose so that the drinking hole on top side is positioned correctly. NUK bottles are BPA Free and come with medium silicone nipples. Available in adorable sea creatures design with sea horses, fishes and whales. Improved Perfect Fit nipple, which is the same shape as Mom's nursing nipple for the Perfect Fit in baby's mouth, just like Mom. 9 out of 10 Babies Accept the improved Perfect Fit nipple, based on research among 200 NUK users. 1-piece NUK Anti-Colic Air System is built into the nipple to help reduce colic, gas and spit-up. Plus no extra parts to clean. The Perfect Fit silicone nipples are available in 2 nipple sizes and 3 flow rates, optimally sized to support baby's growing mouth and appetite. Size 1 is ideal for babies 0 to 6 months and offered in a slow and medium flow. Size 2 is a larger nipple ideal for older babies 6+ months and offered in a fast flow. BPA Free. Dishwasher Safe. Leak-proof nipple sealing hood.