Set of two. Each measures 7'' overall. Rods are coated with cubic boron nitride which is a super abrasive 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. Coarse 40 micron grit. This grit is recommended when you wish to remove stock, for restoration purposes and to aggressively re-shape, re-bevel and re-profile a cutting edge. Fits into the SC204 Sharpmaker sharpening system.