... fastenerS manufacturer for your better choice .1.What’s the specification of our Products ? MaterialsCarbon steel,Stainless steel,Alloy steel,Copper ... #,10B21,1035,CH38F,1039,40ACR...Alloy steel are 35,40CrMo,SCM435,10B38...Stainless steel is SS201,202,302,304,316...copper ... percent C element is 0.18%-0.23% ,is higher hardness than other.2.Fasteners' Head is much thicker ,it is ...