Designed for use with the Lansky Controlled Angle Sharpening System. Diamond Coatings are the most abrasive type of sharpener; they’re ideal for modern, wear resistant tool steels. The extra coarse 70 grit diamond hone is designed specifically for repairing heavy duty damaged edges, reprofiling a knife’s bevel and sharpening modern wear resistance steels. Extra Coarse Grit (70) Diamond Surface (Uninterrupted Diamond Coating)Brass Threaded Insert for Stainless Steel Thumb ScrewErgonomic Plastic HousingN/A