Sharpening stone To keep your knives at their best, it is essential to take care of them. Sharpening and storage are integral parts of their maintenance. This sharpening stone has two sides with two different grit sizes: 400 and 1000. A support is provided to hold it, to help you safely sharpen your accessories. Therefore, it will fit perfectly with all the knives in your kitchen.Material: White corundum (aluminum oxide powder)