TAKE YOUR NURSH TO THE NEXT LEVEL. When your baby’s ready to graduate to a straw cup, these Silicone Straw Conversion Tops are all you need. Designed to fit perfectly on your 8 ounce NURSH baby bottles, the silicone straw turns your existing bottle into a kid’s straw sippy cup. The unique design of the silicone straw combines with your baby bottle’s existing silicone pouch for drinks that only touch 100% silicone. The rotating cover and valved straw included in this conversion top keep the drinks inside the cup and off of your kid.