12.9 grade carbon steel anti tooth cup head hexagonal screw, black full tooth bolt, cylindrical head screw

12.9 grade carbon steel half tooth black cup head hexagonal machine tooth screw bolt elongation

12.9 grade black high-strength carbon steel cup head hexagonal screw with 180 degree adhesive anti loosening full tooth machine thread

12.9 grade black cup head hexagonal bolt machine thread high-strength carbon steel cylindrical head screw

12.9 grade nickel plated cup head hexagonal M2M30 high-strength bolt screw cylindrical head full tooth hexagonal screw

12.9 grade half tooth cup head hexagonal bolt high-strength carbon steel blackened