Surface:Nature,Black,zinc plated,Hot dip galvanized Material:carbon steel,ally steel Standard:DIN,ASME,G Surface:Nature,Black,zinc plated,Hot dip galvanizedMaterial:carbon steel,ally steel,stainless steelStandard:DIN,ASME,GBGrade:4.8,5.8,6.8,8.8,10.9,12.9 Motor nuts