These Forgefix Flat Repair Washers have a large 40mm outside diameter They are bright Zinc Plated for increased corrosion resistance 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 finish It does this by forming a barrier and by acting as a sacrificial anode if this barrier is damaged Zinc oxide is a fine white dust that in contrast to iron oxide does not trigger a breakdown of the substrate’s surface integrity as it is formed The zinc oxide if left intact can act as a barrier to further oxidation in a way similar to the protection afforded to aluminum and stainless steels by their oxide layers