Make quick work of sharpening your knives with these ceramic water stones. Simply soak the stone in cool water for 10 minutes and splash with water periodically while using. Oil is not recommended. Each side is equipped with a different grit, one rougher for removing material and one smoother for polishing. Comes with a silicon non slip base but is recommended to pair with a non-slip bamboo riser base. Select two or three stones to have a variety of grits at your disposal.