ISO 7040 hexagon lock nut, M6, en 10204 3.1 certificate, Article number 70401006ZN5CNT2C. Property class / material: steel class 10, surface finish zinc plated. 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.