Introducing the Premium Whetstone Knife Sharpener Stone by POWERTEC. The POWERTEC 71915 is a high-quality, dual-sided knife sharpening stone designed to deliver edge to edge sharpness and sharpening versatility for your knives, blades, shears, razors, and precision tools. Our grindstone is equipped with color-coded, dual-sided grits, and non-slip rubber base making it perfect for an assortment of grinding, sharpening, and polishing applications. Coarse: 400 Grit for optimal edge sharpening to improve cutting precision. - Fine: 1000 Grit for surface polishing and finishing to extend the life and performance of your knife. Easy To Use Instructions Using water, soak the sharpening stone for 10-15 minutes, then put it on a steady surface such as a benchtop, desk or table. Use the 400-grit side for coarse grinding at a 10 - 30° angle. Use a bit of force to push the knife out, and then gently retract it. This process takes approximately several minutes. Use the 1000-grit side for fine grinding. This process takes about several minutes. After sharpening the blade, clean it with a wet cloth or water, and then dry it. For additional cleaning, you can use a soft brush to clean the sharpening stone and then placed it in a ventilated area to dry out.