Standart : ANSI B18.2.2 1987 Hardness : 71.0-99.5 HRB Surface Treatment : Black Oxide : Blue Zinc Cr3+ : Plain : Yellow Zinc Cr6+ Strength Class : 4.8 Brand : BFC Diameter : 1/4",5/16",3/8",7/16",1/2",9/16",5/8",3/4",7/8",1" Length(mm.) :