A nut having 4 flat sides and an integral washer which extends beyond the flats or periphery.
NSN 5905-01-341-3053
NSN 5965-00-020-1951
NSN 5975-01-098-1640
NSN 5925-01-406-3490
NSN 6645-00-279-1777
NSN 5910-01-227-1939
NSN 5965-01-366-4650
NSN 5945-01-651-7403
NSN 2925-00-010-9609
NSN 6130-00-568-5855
NSN 5985-01-634-0635
NSN 5930-00-238-0607