One-of-a-kind 4 inch Concrete Coasters with real rocks. Rough cut, polished and finished. Cork bottoms available in original and black. Coasters can be used outside and indoors; heavy duty REAL concrete. A great gift for any rugged loving person in your life! NO ONE WILL HAVE THE SAME COASTER SET!! (There may be minor deviations and non-integral flaws in coasters such as the heights by millimeters since they are rough cut and not factory made)