These straw covers are 0.4 in/10mm compatible with Stanley 30&40 oz tumbler straw. It includes 6 pcs different color bow design. Made of a high-quality food grade material, BPA free, odorless, durable, and reusable. They can be hand washed and machine washed. The silicone straw tips can perfectly cover your straw to prevent dust form entering and spills from happening.