Norton Combination Waterstone: 4000/8000

The 4000 grit side is fine, used for edge maintainence. The 8000 grit side is extra fine used for mirror finishes / polishing. In order for Waterstones to work properly, they must be soaked in water prior to use and the surface must be kept wet to develop the sharpening slurry. Because Waterstones are soft, they must be periodically flattened to maintain their effectivness