... Material: 40Cr Grade: 10.9 or 12.9 Rear hub bolt with dual ring 1.Surface:black,phosphated,galvanized.. 2.Grade:4 ... .9 3:Material:mild steel,45# steel,40Cr,42CrMohigh strength hub bolt, hub bolt and nut, high strenght bolts 10.91. Surface ... ) Strict quality control;(3) very reasonable and competitive price. Rear hub bolt with dual ring