A nut having 4 flat sides and an integral washer which extends beyond the flats or periphery.
NSN 5999-01-538-7388
NSN 5950-01-283-9125
NSN 6620-01-152-9453
NSN 5999-01-316-2098
NSN 5965-01-179-7749
NSN 4140-01-348-9029
NSN 5996-01-274-1025
NSN 6620-01-355-4339
NSN 6650-01-497-1773
NSN 5998-01-200-6974
NSN 5945-01-133-3627
NSN 5999-01-033-0593