The Naniwa 5,000 Grit Nagura Stone. While it is called a stone it is not intended to be used on your knives, instead this product is used to maintain your stones. This is a 5,000 grit Nagura stone so use it to clean and prepare your 5,000 grit waterstone. 2-3/8" x 1-3/16" x 3/4" (60mm... See More