Fasteners Etc., Inc. offers structural flat washers per ASTM F436 standard. These flat washers are manufactured from higher grade steel that is heat treated to further increase the strength, well beyond that of our standard flat washers or thru hardened flat washers. Most projects that require a structural washer will also require a structural bolt and structural nut. Allow Fasteners Etc., Inc. to be your one stop for all products required, certifications available upon request. If you have a large jobsite listing, please contact us for a special quote based on volume.