It is an impression used for stainless steel Sannde kitchen knife. # 3000 Because I never used the grindstones around and I purchased it, the amount per volume is a deciding factor. It is unexpectedly slimy, but not to say it's dangerous to catch on. It seems that if you finish a universal kitchen knife for home use, it seems to be sufficient performance, especially stainless knives (due to the characteristics of steel).