TigerSharp, 4 pack. These blades are a feature of the TigerSharp Technology. This replaceable blade technology means your knife never needs to be sharpened, simply remove the dull blade and slide a fresh one between the guides. Titanium Bonded blades are 3x harder than steel and stay sharper longer. Resists corrosion and adhesives. Includes 4 smooth replacement blades. For use with TigerSharp fixed blade knife #18560.