ANSI B18.2.7.1M flange screw [1]standards:ANSI B18.2.7.1M [2]material:carbon Steel ,Stainless steel [3]surface:zinc,black ANSI B18.2.7.1M metric 12-spline flange screwWe also supply hex head bolt, heavy hex structural bolt,hex fit bolt,hex flange bolt,flat countersunk square neck bolts,cup head nid bolts,single-head bolt,double head bolt.. ANSI B18.2.7.1M metric 12-spline flange screw