This set of 4 officially licensed Major League Baseball Pittsburgh Pirates coasters is made of Italian Botticino Marble, quarried in Verona, Italy. After being cut and smoothed, the image is hand-printed onto the surface of the stone. Because the marble is naturally a little porous, the image is absorbed by the surface of the stone. The image will never peel or flake off. The coasters are then backed with a thin layer of cork to avoid slipping on hard surfaces. Keep your coasters handy and show your team pride by displaying them in the decorative iron holder (included). These coasters are a great addition to any fan's home. Classic in style and featuring colorful team they will fit in with any decor. The set of 4 coasters comes packaged in a box suitable for wrapping as a gift. Clean your tumbled marble coasters with soap and water. Please do not use any abrasive cleaners or pads as they will scratch the image.