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&40 oz tumbler with handle straws! Food-grade silicone material: unlike ordinary PVC material straw covers cap, our straw covers cap is BPA free, and there is no unpleasant smell, you can use it without worry, cleaning it is a breeze! 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 9-10mm 0.35-0.4inchDust-Proof Reusable Straw Tips Lids. Package: Good choice for a gift,this mini cup stanley cup straw cover,It looks very cute, easy to put on and take off when using, the main thing is reliable quality. It is the best gift for cups lovers.