Made of sandstone material, these coasters are super absorbent, and will soak up any extra moisture from your beverage! There is a handy divot on the side for easy removal for cleaning. Wipe clean with soap and water. Each car coaster measures approx 2.5" circle and are 1/4" thick. PLEASE NOTE: It is our experience that colors will vary since the ink is absorbed into the coaster. We have found solid dark colors absorb more than others. Each car coaster measures approx 2.5" circle and are 1/4" thick.