Food-grade silicone material: unlike ordinary PVC material straw covers cap, and there is no unpleasant smell, you can use it without worry, cleaning it is a breeze Perfectly compatible: Unlike most straw caps on the market, this straw cover is specifically designed for stanley cup straw. You don't have to worry about the wrong size, perfectly compatible with stanley 30 and 40 oz tumbler with handle straws! Leak-proof: prevents the straw from being contaminated by dust and spittle in the air, and also prevents mosquitoes from entering the water cup, keeps the straw and cup hygienic. Precisely: fit stanley large straws with a diameter of 9-10 mm 0.35-0.4 inch. Package: Flower straw cover,this straw cover it looks very cute. Food-grade silicone material: unlike ordinary PVC material straw covers cap, and there is no unpleasant smell, you can use it without worry, cleaning it is a breeze.