Shapton Kuromaku Japanese Whetstone #320 Grit (Blue-Black) K0709 Shapton ProfessionalKUROMAKU is the world's first set of colour coded sharpening stones, each colour representing a different grade of coarseness in the range. The storage case makes it easy to carry the stones, and can also be used as a sharpening base. These stones are Waterstones but can also be used as oilstones. Every stones case can be stacked for easy storage and helps identify the grit quickly by the colours. Rubber feet on the base of the case provide a stable