A washer or cone or disk shape with a centrally located hole, designed to accommodate a flat or oval head screw and provide additional bearing area on the material being fastened. It may or may not have a flush flange feature.
NSN 7035-01-365-9610
NSN 5965-00-900-6401
NSN 5935-01-470-6459
NSN 6650-01-229-4224
NSN 2925-01-094-4771
NSN 6110-01-194-2217
NSN 5945-00-293-8333
NSN 6145-00-627-9010
NSN 5895-01-522-2485
NSN 5985-01-246-3725
NSN 6650-01-067-0132
NSN 6105-00-249-2897