A nut having an externally splined sleeve which holds it in position when forced into a hole of slightly smaller diameter.
NSN 5950-00-148-4230
NSN 6220-00-724-0400
NSN 5835-01-384-3206
NSN 5920-00-715-1572
NSN 5895-00-525-3295
NSN 5935-00-670-7895
NSN 7035-01-320-7453
NSN 6150-00-150-8838
NSN 5985-01-443-5425
NSN 7035-00-111-4389
NSN 6240-00-861-1372
NSN 5990-00-689-5736