The unique Autoseal technology allows for convenient one-handed drinking; there is no need to remove a lid or open a spout. You simply press the Autoseal button to drink. Once you release it, the cup automatically seals itself. The drinking opening is closed except when drinking, making it 100% drip and spill-proof. Thanks to their simple design, Autoseal lids are easy to clean and dishwasher safe on the top rack. The lids also seal directly at the drinking opening to prevent any residual liquid from being trapped.