The DC521 is a bench stone with uncommon characteristics, offering two different types of stone. The yellow side is a fast and aggressive diamond stone, while the dark side is a slow and very fine ceramic stone. Both surfaces will remain flat throughout their lifespan, which is essential for achieving perfect sharpening results. The diamond stone works quickly and should be used if the edge is very thick. The sharpness achieved is usually sufficient for everyday tasks. The ceramic sharpening stone works much more slowly and provides a smoother, finer edge when needed. For tools and kitchen knives, this bench stone is among the best available. It comes in a beautiful gift box and includes sharpening instructions.