A nut having an externally splined sleeve which holds it in position when forced into a hole of slightly smaller diameter.
NSN 5925-00-186-8669
NSN 5920-01-084-2508
NSN 5965-01-204-8505
NSN 6220-00-505-1599
NSN 5999-01-270-2302
NSN 5915-01-290-3885
NSN 6685-01-197-3838
NSN 7035-00-849-5526
NSN 6135-01-067-8331
NSN 5935-00-237-2524
NSN 6130-01-264-9276
NSN 5996-00-753-1599