It is suitable for hardness measurement of quenched, Quenched and tempered, annealed and chilled castings, malleable castings, hard alloy steel, aluminum alloy, copper alloy, bearing steel, etc. It is also applicable to surface hardened steel, material surface heat treatment and chemical treatment layer, copper, aluminum alloy, sheet metal, galvanized, chrome, tin materials, bearing steel, cold hard castings, etc.