Dual sided whetstone with fine and extra-fine surfaces. A must for sharpening sashimi knives to their ultra-fine edge. With a sharp knife you can cut food with the least effort, least damage and best presentation. Sharpen your knives after every day's use. 8.5 x 2 x 1 inches. #250 (aratoishi)/ #1000 (naka-toishi) grits. Made in Japan.