【Perfect Size】 The inner diameter of the straw toppers is 0.4 inch(10mm), compatible with Stanley 40 OZ tumbler straw and most straws of 0.4 inch(10mm). Come on to have the perfect size straw cap for your Stanley Cup. Sincerely Remind: Only for Stanley Cup 30oz/40oz which is 0.4inch (10mm) Straw, Other Brand Dumbler or Cups may NOT fit because of the Straw is 0.24-0.32inch (6mm-8mm) 【High Quality Material】 Made of food grade silicone which is safe. Durable for a long time to use, non-slip and easy to press on the straw. Reusable by washing it with your hands or throw it into the dishwasher. 【Unique Design】 The package contains 10 pieces of silicone straw covers, Cartoon styling is more than cute, suitable for Stanley cup better. 【Protect Drinks】 The straw cover can prevent spilling water when indoors, prevent kids kids and pets knocking over your stanley cup. Great prevent the straw from being contaminated by dust and spittle in the air, and also prevents bugs from entering the water cup. 【Great Gift】 Small shape and easy to carry. Suitable for various outdoor activities such as party, travel and camping. You can also share them with your relatives and friends as a gift. The silicone straw lids are made of high quality materials, safe and odorless, durable and reusable. After you clean and dried, you can stored for next time. Airtight seal, dust and splash proof, especially suitable for outdoor activities.