DIN 6921 hexagon head screw with flange, M16 x 55, Article number 6921816055. Property class / material: steel 8.8, surface finish plain. Hexagon Head Screw with Flange manufactured to DIN 6921 with ISO metric (M) thread, coarse pitch, partially threaded. Standard parts to the same standard, property class, dimensions and surface finish are interchangeable between manufacturers; confirm the controlling standard revision, any class-society or application approval, and the mating thread before substitution.