These beautiful acid stained concrete coasters will look amazing on any coffee table. Coasters measure 4" x 4" x 3/8".They are made from extremely durable concrete. With a one of a kind acid stain for a very unique color. And are finished off with a UV and mold resistant concrete sealer . Which will require no additional up keep. Just wipe them clean. They also have felt buttons on the bottom so they will not scratch your tables. The unique quality with concrete is that no two coasters are the same. They are unique to you and you only. It is impossible to get the same coaster twice.