DIN 125-A round flat washer (form A), 21 x 37 x 3 mm, Article number 125210GEO. Property class / material: steel 140 hv, surface finish zinc flake, silver. Round Flat Washer manufactured to DIN 125. 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.