These shredder blades feature a 50-55HRC high-hardness alloy steel blade head, professionally heat-treated for exceptional hardness and toughness. The stepped blades edges are sharp and burr-free, delivering consistently even granules of various plastics. If the blades wear, simply re-grind the stepped surface to restore their sharpness. The blades can be reused multiple times, significantly reducing blade replacement frequency and saving costs.