A nut having an externally splined sleeve which holds it in position when forced into a hole of slightly smaller diameter.
NSN 6135-01-334-3935
NSN 5930-00-814-8851
NSN 5945-01-040-3661
NSN 6105-00-914-2232
NSN 5895-01-144-8504
NSN 5930-00-577-0404
NSN 5905-01-562-8385
NSN 5945-00-258-5061
NSN 5960-00-853-0056
NSN 5990-00-115-5851
NSN 5895-01-130-0907
NSN 4140-00-078-9357