机器螺钉和垫圈组合件 screws and washers assemblies 自攻螺钉和垫圈组合件 tapping screws and washers assemblies 薄型带孔内六角圆柱头螺钉 hexagon socket head cap screws with hole,low head ..
Usually there are 12 categories which are bolt , stud, screw, nut , selftapping screw, wood screw, gasket, retainerring, pin, compositemember, bolting, and soldering lamp.