The soft silicone spout is uniquely designed to prevent drips and spills while being gentle to gums and emerging teeth. The No Spill 360 straw follows the liquid allowing your child to drink in any position, including upright,Do not microwave; do not boil; do not steam sterilize. Only the 360 straw parts can be boiled, steam sterilized, and are also top rack dishwasher safe