Spyderco Triangle Sharpmaker Cubic Boron Nitride Tri-Angle Sharpmaker Rods 204CBN. Cubic Boron Nitride (CBN) is a superabrasive that is second in hardness only to diamond. It offers superior abrasion resistance and thermal conductivity compared to conventional abrasives like silicon carbide and aluminum oxide, making it the preferred abrasive in many advanced industrial grinding applications. Now you can combine the advantages of this fast-cutting abrasive with the convenience and ease of use of Spyderco's Tri-Angle Sharpmaker with these CBN-coated Sharpmaker rods 7" X 0.5" (178mm X 13mm). Sold in a pair, 204CBN triangle rods fit into the 204 Sharpmaker sharpening system. Use them dry, without oil, water or lubricants. To Clean: rinse in fresh water. By Spyderco.