A nut having an externally splined sleeve which holds it in position when forced into a hole of slightly smaller diameter.
NSN 5935-01-343-1299
NSN 6620-01-048-4145
NSN 7035-00-111-4389
NSN 6240-00-459-5367
NSN 6610-01-484-8980
NSN 6220-01-253-0380
NSN 5975-01-192-8694
NSN 5965-01-323-0501
NSN 5985-01-094-8306
NSN 6240-00-761-6643
NSN 5965-00-182-7928
NSN 6105-01-414-4637