Gorgeousness meets utility. You'll be guaranteed that your whiskey glass will not be sticking to this coaster. Comes in a set of 4. Material: Concrete w/ a cork base Dimensions: 4" w x 5/8" h (per coaster) Designer: Mike Garman Our concrete work is all individually hand cast from custom made rubber molds. Colors are integrally mixed into the concrete and results in each piece being unique. We use recycled materials and are able to create a finished product 30% lighter than traditional concrete. Although the sealer is food grade and safe we don't recommend using these for direct food contact. Natural voids occur during casting and some pieces will have very small pin holes. Do not submerge in water. Wipe clean with mild soap and water.