... Usage:JIS#10-JIS#240(1)It can make the abrasive tool to grind the great hardness material, such as ... used for sandblasting, such as precious metal, the gold, crystal, the glass and cowboy wear. JIS#280-JIS#4000(1 ... , silver jewellery, the eye glass, bearing and any kind of precision instrument.(2)It can be used in manufacturing the ... -5,5-8mm and 180,200,240,280,320F Super Single Crystal Aluminium Oxide