Silverline - DOUBLE SIDED DIAMOND FILE (320 GRIT) - 103532 Double sided 320 Grit 50 x 150 diamond file. Features a perforated surface for the sharpening of larger tools and a standard surface for smaller or finer work. Ideal for chisels, router cutters, plane blades and most hand tools. May be used dry or with a little water for lubrication. Dry thoroughly after use.