ISO 7040 hexagon lock nut, M12, en 10204 3.1 certificate, Article number 704012FLZNNC. Property class / material: steel class 8, surface finish zinc flake, silver. Hexagon Lock Nut manufactured to ISO 7040 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.