1. It can produce grinding slurry. Compared with oilstones, it can achieve effective grinding with less pressure. 2. One side of the double - sided oilstone is 4000 grit, used for maintenance and fine grinding; the other side is 8000 grit, used for polishing steel blades. 3. When using water or oil as a lubricant, it is very convenient to clean. 4. The blue plastic flip - top box has a non - slip design and can be used as a support for the oilstone during grinding. 5. This Japanese 4000/8000 grit double - sided oilstone can produce grinding slurry for effective grinding. One side is 4000 grit for maintenance and fine grinding; the other side is 8000 grit for polishing the blade. 6. The size of this oilstone is 18*6*3 cm (height × width × depth). It is suitable for use on the workbench, easy to clean with water, and comes with a blue plastic flip - top box. 7. The removable box lid has a non - slip design and can be used as a grinding platform to fix the oilstone when used on the workbench. 8. A whetstone is a grinding surface used to grind and sharpen the blades of steel cutting tools, such as chisels, knives, scissors, hand scrapers, and planes. 9. Grinding is the process of adjusting the blade angle and reshaping it by grinding the metal part to create or re - repair the blade. 10. Package contents: 1 whetstone. 11. Note: Light and different displays may cause the color of the item to vary slightly from the actual product. The allowable error for the size is ±1 - 3 cm.