Both nipple materials have their own special characteristics. NUK silicone nipples are made of a high-quality polymer synthetic material. This transparent silicone is heat and age-resistant and very easy to clean. Latex is a natural rubber product that is flexible, bite and tear-resistant. Since latex is a natural material, edible fats and exposure to direct sunlight may age it somewhat quicker than silicone. Which material you choose depends on your individual wishes or preferences and those of your baby too. Of course, you can always switch from one type to the other.