... :AISI304,316,420C,440C Size:0.8mm-150mm Grade: G10-G1000 Standard:ISO 9001:2008/SGS test ... a type of modern steel and famous for its high corrosion resistant, wear resistance, strength and hardness qualities ... Rockwell or higher. Martensitic Grades are known for high hardness and allowances must be made for poor weld ... ,G10Any further Information,Plz contact us! 8mm High Quality Stainless steel ball