ISO 7380-1 button head with hex drive, 010.9 M16 x 50, Article number 73801016050. Property class / material: steel 10.9, surface finish plain. Button Head with Hex Drive manufactured to ISO 7380-1 with ISO metric (M) thread, coarse pitch, fully 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.