NIUBI 3000/8000 Grit Combination Corundum Whetstone Knife Sharpening Stone / Waterstone Knife Sharpener Double-sided sharpening design(3000 grit for coarse grinding and 8000 grit for fine grinding). Special proportioned white corundum made waterstone, high hardness and wearproof,Suitable for top grade kitchen cutter, outdoor knife, precision tool. Equipped with silica gel non-slip base, guarantee the safety sharpening kitchen knives, scissors, outdoor knives and all types of steel tools. In addition, with these stones the worn material and the water form a slurry, which in conjunction with the stone, sharpens and polishes the blade. Make a great gift for birthday, Mother's Day, Christmas or just to make your knife enthusiast smile.