A nut having an externally splined sleeve which holds it in position when forced into a hole of slightly smaller diameter.
NSN 6145-01-103-3909
NSN 5985-00-836-3042
NSN 5925-00-452-1270
NSN 5990-01-582-1977
NSN 5999-01-305-3632
NSN 6650-01-446-8752
NSN 6645-01-425-2330
NSN 5925-00-574-2522
NSN 6110-00-239-9248
NSN 6620-01-467-2111
NSN 6105-00-060-7024
NSN 5920-01-302-6417