Our spill-proof stopper fits into the straw hole in the lid, creating a seal and holding the straw in place, making it easy to enjoy your favorite beverages on the go. The cross-opening design ensures that air enters when drinking water, promoting a healthier drinking experience by preventing the formation of a vacuum and allowing for smoother sips. Made from food-grade silicone, this spill-proof stopper is reusable and easy to clean, making it a sustainable and hygienic choice for everyday use. This silicone spill-proof stopper prevents water from spilling out of the straw, keeping your drinks contained and free from dust or debris, ensuring a clean and enjoyable drinking experience. Suitable for various occasions such as home, living room, bedroom, school, outdoor activities, and travel, this spill-proof stopper is a versatile accessory that can be easily carried wherever you go. Item Name: Spill-Proof Stopper Material: Silicone Features: Food Grade, Leakproof, BPA Free, Reusable Size Details: Suitable Water Cup: 30oz/40oz Suitable Straw Length: 9cm-9.5cm/3.54"-3.74" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 Set of Spill-Proof Stopper