COMPATIBLE SIZEOur straw caps are suitable for all types of straws with an outer diameter of 8~10mm, The inner diameter of the straw toppers is 0.4 inch (10mm), compatible with Stanley 40 OZ tumbler straw and most straws in diameter 0.4 inch. They are tight enough not to fall off easily. Please note that our package only includes silicone straw stoppers, straws are not included. Please confirm the diameter of your straws before buying. SAFE MATERIALThe silicone straw lids are made of high quality materials, BPA free, 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. You can use it with confidence. PACKAGE INCLUDEYou will receive 4 pcs cute straw cover caps with Mini Cup styling, delicate and cute. It prevents the straw from being contaminated by dust and spittle in the air, keeps the straw and cup hygienic, let you drink with confidence anytime. EASY TO USEThe small flexible straw protector is easy to put on and take off. With good air-proof function it can not only defend dust into drinks but also prevent drinks from spilling. raw topper is portable. You can carry it anywhere, such as party, out shopping, travelling, camping. It's practical tool for daily usage. PERFECT GIFTSuitable as a wonderful gift for birthday party, wedding, home decor, straws party and outdoor activities for your family and friends. Kids will definitely love the beautiful straw cover decoration!