10mm Straw Covers: Amreich straw cover is compatible with all type 0.4inch diameter includes stanley 20oz, 30oz, 40oz cups, yeti cups etc. it's right size straw accessories of your stanley cup. please note that package only includes straw covers, straw is not included. Safety Material: The heart design straw covers are made of food grade silicon, which is no-toxic, no smell, cold and heat resistant, safe for long-term use. it's reusable and dishwasher washable. Protect Your Drinks: The straw cover is not only cute to decorate your straws but also keep your drink safe. when you're at home, the straw cap prevent dust, pet's hair,mosquitoes entering your cups. prevent your pet from licking your straws. when you bring your cup outside, the straw topper seal your straw perfectly,It prevents drinks from spilling during moving, especially suitable for outdoor activities, such as walking, camping, hiking etc. Easy to Use: The silicon straw tips consist of the bottom part of the retaining ring and the top part of the cap stopper and connected by silicone thread in the middle . Bottom part can be directly fixed on the straw, when you drink, pull the top part out, when you're not drink, put the top cap back. Cute Gifts: The straw cover set includes 4 pcs heart deign straw toppers. they are creative decorations for your stanley straw cup. Suitable for all kinds of parties like straws party and wonderful gifts for friends and family. Don't worry about getting the wrong size, if it doesn't fit your stanley or other cups, we will provide 100% refund.