Standard:Hexagon Bolts/DIN 931 Size:M5-M42 Material: Mild Steel,Medium Steel,40Cr Grade:4.8,8.8,10.9,12.9 Surface:Black,Zinc Standard:Hexagon Bolts/DIN 931Size:M5-M42Material: Mild Steel,Medium Steel,40CrGrade:4.8,8.8,10.9,12.9Surface:Black,Zinc,Plain Hexagon Bolts/DIN 931