DIN 6799 retaining washer, 9 mm, Article number 6799C409. Property class / material: c4, surface finish plain. Retaining Washer manufactured to DIN 6799. 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. Applications: load distribution and locking under bolt heads and nuts in machine building, structural steel, plant maintenance and marine outfitting.