Made with premium silicon carbide, the 400-1000 grit green side is suitable for any daily sharpening, such as repairing coarse knives and polishing knives, the 3000-8000 grit red side will help you make knives smoother after using the 400-1000 grit. Comes with two 7 x 2.2 x 1.1 inch sharpening stones, a quality bamboo base and non-slip rubber bases, a flattening stone, an angle guide for beginners and a quick user guide with all the good tips for sharpening knives, can also be a great housewarming gift idea. No oil needed, just put the stone in water for 10-15 minutes before use and it is ready to use. You can always add water while sharpening; water will have a great lubricating effect on sharpening and help you save effort. One stone, unlimited professional knives. Sharpening stones are compatible with all types of knives, including chef's knives, hunting knives, pocket knives, Japanese knives, butcher knives, paring knives, barbecue knives, scissors, wood chisels, and blades. Also suitable for hatchets, axes, carving tools, and gardening tools. This white corundum grinding stone is faster to depulp and has strong self-sharpening power. When the white corundum grinding stone is sharpened, new edges and corners appear very quickly, and the self-sharpening property is good. Therefore, the grinding stone does not need to be dressed very frequently, and work efficiency can be improved.