The Faithfull Diamond stones will sharpen steel, HSS and tungsten carbide tools and may also be used to abrade glass, ceramic tiles and porcelain. Diamond stones may be used dry or with water as a lubricant. Always dry the stone after use and before storing. Clean the stone occasionally, using soapy water and a soft brush. A 4-sided diamond sharpening stone supplied with a worksafe surface gripping base for quick, easy and effortless sharpening of any blade. Grits Fine (red) 600 grit, Medium (green) 400 grit, Coarse (yellow) 300 grit and Extra Coarse (blue) 200 grit.