【Perfect Size】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(10mm).Customize the perfect size straw cap for your Stanley Cup!.【Food Grade Material】Straw covers cap are made of food grade silicone, durable, reusable. Airtight seal, dust and splash proof..【Resuable Use】Durable for a long time use,non-slip and easy to fix on the straw.It’s washable by hand or in the dishwasher. Dry it and store it for next time use again..【Protect Your Drinks】With good air-proof function it can not only defend dust into drinks but also prevent drinks from spilling..【Perfect Gift】Our Straw Caps Covers are perfect for decorating your sippy cups. Creative cartoon shape, cute and very decorative. The perfect gift for friends and family.