12.9 bolt grades: 1.Spec:DIN,JIS,ASTM,GB,UIC 2.Surface:black, HDG 3.Grade:4.8,8.8, ... 10.9,12.9 4.Material:Q235 ... ,45#,40Cr ASTM DIN GB Standard High strength 12.9 bolt grades with large hexagon head for steel structures ... your visit! ASTM DIN GB Metric High strength hex head 12.9 bolt grades