The Spyderco Diamond Tri-Angle Sharpening Stones are steel triangles blanketed in a bonding agent then covered in diamond particles. Diamond hard abrasives are recommended when you wish to remove stock, for restoration purposes and to aggressively re-shape, re-bevel and re-profile a cutting edge. The Tri-Angle Stone is 7" x 0.5" and designed to fit the Spyderco Sharpmaker system. Use them dry, without oil, water or lubricants. To clean rinse in fresh water. FeaturesFits the sharpmaker baseAggressively re-shape, re-bevel and re-profile a cutting edge