Hexagon head bolts ISO 4017 ISO 4017 1.7218 +QT (25CrMo4) zinc plated with 3.1 certification M16x50 1.000 pcs ISO 4017 1.7218 +QT (25CrMo4) zinc plated with 3.1 certification M20x50 2.000 pcs ISO 4017 1.7218 +QT (25CrMo4) zinc plated with 3.1 certification M20x80 1.000 pcs