Enlarged Washer A fastener that has the appearance of a flat disk with a smooth cylindrical hole in the middle, the diameter of which is slightly larger than the diameter of the metric product with which it is used. The difference between R and V in the hole: R - cylindrical hole, V - square hole.
Scope DIN 440 is most often used in the installation of wooden structures, due to its ability to increase the clamping area. But it is also used in mechanical engineering, and in construction, where a strong support surface is needed at the point of connection.
Material stainless steel.
Coating Zinc (Plated) protects against corrosion if fasteners are intended to be used in aggressive environments.
Analogs GOST 6958-78, ISO 7094