Please measure your mug mouth inner diameter size: This lid is suitable for many stainless steel insulated mugs with a inner diameter of 3¼ inches, the most typical is 20 oz Ramblers. If you can patiently spend a little time to measure the INNER DIAMETER of your mug mouth before deciding to buy, it may save you the trouble of returning or exchanging goods because the unfit size. Perfect FIT: This lid fit well for 3¼ inch diameter cup.In addition, it's also fit for 12 oz coffee mugs with 3¼ inch mouth, but not for 20 oz skinny tumbler.Anyway,focus size of inner diameter! Safe Material : Made of food grade crystal clear AS plastic which is BPA free, Eco-friendly, Sturdy and durable Non-toxic and dishwasher safe. Perfect Design : We have improved the water stop ring. Good air tightness design keeps your beverage warm and cold longer. Drink hole on the top for easy sipping, It is straw friendly. The transparent lid design is convenient for seeing what you are drinking and how much is left. Perfect Service: We provide 100% satisfaction guaranteed. If you are not satisfied with your purchase you can request a refund or exchange within 35 days or 5 weeks. Wotermly 4 Pack Tumbler Replacement Lids for 20 oz Tumblers, Spill Proof Splash Resistant Lids Covers Fit for Rambler and More Coffee Mugs, 4 Lids