Hardness is a property of the material of the cutting edge of the pliers that determines its resistance to wear and its ability to maintain a sharp cutting edge. Hardness is usually measured in Rockwell Scale (HRC) units and is a key factor in selecting pliers for specific applications. Higher edge hardness provides longer life and better performance when cutting harder materials. High hardness is essential for pliers used in industrial and professional environments where they are subjected to heavy use.