Aluminium oxide stone double grain for wide spectrum applications.Artificial combination stone with 2 grains for restoring and sharpening the cutting edge of chisels, plane irons etc..Side A: rough side with 120 grains/cm², suitable for removal of dents in the cutting edge, to even or straighten out cutting surface.Side B: fine side with 400 grains/cm², suitable for sharpening of cutting edges and smoothing of cutting surfaces.We suggest the use of this stone before finishing with natural stones.Application: dry, oil or water.Cleaning: rub stone with sandpaper and water