ISO 4032 hexagon nut, M20, en 10204 3.1 certificate, Article number 40320200GEO3BVLC. Property class / material: steel class 8, surface finish geomet silver. Hexagon Nut manufactured to ISO 4032 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.