Grade: G10-G1000 Hardness:AISI304 and AISI316 are soft materials. For AISI420C after heat-treatment, the hardness is between HRC54-60. For AISI440C is HRC58-62 Quality standard:ISO 9001:2008/SGS test report/ROHS report Feature&Applications: ss 304 stainless steel ball is the most widely used in the market,it can be used in iatrical instruments,chemical industry,plastic hard ware,scent bottle sprayer,valve,nail polish,air condition,medical material,automotive fittings.