These forgefix din 125 flat washers are zinc plated for increased resistance to corrosion washers provide a smooth surface for the nut or bolt to bear on making it less likely to loosen as a result of an uneven fastening surface the main purpose of a washer is to distribute the load under a bolt head or the nut face application on all manner of bolting applications can be used with all types of bolts and nuts zinc coatings prevent oxidation of the protected metal to create a longer lasting finis