10'' overall. Grit: Extra fine. Precisely micronized monocrystalline diamond coating. Convex and concave diamond surface. Affords longer sharpening strokes over traditional slip stones providing 0.0625'' radii tapering to 1.000'' radii accommodating all curved gouges. Can properly maintain a wide range of curved surface tools like in-cannel and out-cannel gouges, carving tools and wood turning tools. Hang packaged.