PROFESSIONAL "S" are the classic knives for the professional kitchen. The knives are made of proprietary special formula steel that has been perfected for over 280 years. Combined with ZWILLING's signature ice-hardening technique, these FRIODUR blades are harder, sharper, they will NOT STAIN or chip and they retain their sharpness longer.Honed and hand-finished by the most skilled artisans, the knives' laser-controlled edge is incredibly sharp. The sturdy bolster provides the right balance and acts as a finger guard. Precision-forged from a single piece of solid steel, these threerivet handle knives deliver optimum balance and safe handling. Professional chefs worldwide trust the tradition and quality of these impressive knives.