Silicone coffee mug lids made from food grade silicone rubber (BPA free, non-toxic, reusable and safe). Size: Inner diameter 3.5 inch, outer diameter: 3.9 inch Suitable for standard coffee mug/cups with outer diameter of 3.5" - 3.9". (Please note the size). These coffee mug lids have a drinking hole and air intake and are stamped "Caution Contents Hot". Suitable for ceramic, glass, plastic, paper or any other material cups. Dishwasher & Microwave safe. These lids fit 12 oz, 15 oz & 17 oz mugs. Great to keep your hot and cold drinks from spilling.