DIN 439-B hexagon nut (form B), M39 x 3, left-hand thread, Article number 439L393001. Property class / material: steel class 4, surface finish zinc plated. Hexagon Nut manufactured to DIN 439 with ISO metric (M) thread, fine 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.