Spyderco Sharpener Tri-Angle Cubic Boron NitrideThe Spyderco Superabrasive Cubic Boron Nitride Tri Angle Sharpening Stone Rod is a superabrasive that is second in hardness only to diamond. The set includes two sharpening tri angle stone rods in silver color. This cubic boron nitride triangle stone offers greater abrasion resistance and thermal conductivity than conventional abrasives like silicon carbide and aluminum oxide. It is a preferred abrasive in most advanced industrial grinding