DIN 6799 retaining washer, 4 mm, Article number 679904PHM. Property class / material: steel, surface finish zinc phosphated. 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.