These coasters have a perfect grip on the drinks places on them, making it harder to split them from the glasses. They are made from top quality food grade silicone to last you for years to come, Non Slip, Non Scratch, Non toxic, durable, washable & reusable., Size: Coaster-4 1/4" L x 4 1/4" W x 1/8" H, Package-5 1/2" L x 4 3/8" W x 1/2" H., Material: Silicone, Care & Clean: Dishwasher Safe, Includes: 4-PC, Suitable for any drinking glasses, coffee mugs, tea cups, tumblers, flasks, etc.