Flat washers are great for adding resistance to your bolts and screws that will provide a greater bearing surface under the fastener to prevent them from boring into the surface and weakening it. Used behind a nut or screw head to distribute load and to prevent material from buckling or screw pull-through. Washer sizes are specified by the bolt or screw diameter and should be matched to ensure proper fit. Flat Washers are free from burrs and have smooth, flat surfaces. These washers are finished with a zinc finish and have good corrosion resistance.