FELIX knives are sharp for a long time. But even they need sharpening some time. A particularly simple and gentle way to grind is sharpening with the whetstone set. It combines various grain sizes. Two sides for two grinding steps. Unevenness is ground down with the rough side of the whetstone. The precision-grind is carried out with the other side. The knife is thus sharpened precisely and the cutting edge is polished.