Bolt, Nut manufacturer / supplier in China, offering Premium Black Color Zinc-Finished Double End Stud Bolts Carbon Steel Material with Zinc Finish Black Color Double End Stud Bolts, High Standard Carbon Steel Zp Gal ASTM A325 A307 Gr2 Gr5 193 B7 Black Oxide Grade 4.8 8.8 10.9 12.9 Double End Wheel Stud Bolts, China Manufactured Thread Studs Metal Bolts Zinc Plated Black Grade 4.8 8.8 10.9 DIN938 DIN939 DIN940 and so on.