TRIMEC, we look forward to your visit. If you have any questions, please feel free to contact us. ✨ Made of high-quality silicon carbide. The green side, grit 400-1000, is suitable for all daily sharpening work, such as repairing wide-edged knives and polishing knives. The red side, grit 3000-8000, helps you make knives smoother after using grit 400-1000. Comes with two 18cm x 5.6cm x 2.8cm sharpening stones, a high-quality bamboo base and non-slip rubber soles, a flattening stone, a beginner's angle guide, and a quick guide with the best sharpening tips. It also makes a great housewarming gift idea. No oil is required. Simply soak the stone in water for 10-15 minutes before use, and it's ready to use. You can add water at any time during sharpening. Water provides optimal lubrication and simplifies use. One stone for a multitude of professional knives. The sharpening stones are suitable for all types of knives, including chef's knives, hunting knives, pocket knives, Japanese knives,