A nut having an externally splined sleeve which holds it in position when forced into a hole of slightly smaller diameter.
NSN 6110-00-516-8645
NSN 5855-00-483-0020
NSN 4140-00-953-9335
NSN 6145-01-459-8150
NSN 5915-00-226-3403
NSN 5945-01-151-2936
NSN 5920-01-069-4999
NSN 6645-01-055-5465
NSN 5999-01-644-2727
NSN 4140-00-148-7013
NSN 6240-01-178-5604
NSN 5960-00-034-7925