3/8 in.
A nut having a sleeve portion on its under side, which can be crimped or clinched to hold the item in place when inserted in a hole.
NSN 6320-00-174-1362
NSN 5998-01-286-4389
NSN 5920-01-097-9927
NSN 6110-01-031-9670
NSN 5930-01-302-0509
NSN 5996-01-439-6047
NSN 6240-01-395-6360
NSN 5996-00-247-0854
NSN 5855-01-453-6384
NSN 6150-01-500-1918
NSN 6220-01-364-2130
NSN 4140-01-372-5718