A hexagon nut having a concave face and a concave or slotted top.
NSN 2925-01-624-5647
NSN 5998-01-429-5309
NSN 5950-01-081-3557
NSN 5935-01-634-0668
NSN 2925-01-368-5773
NSN 5960-00-241-2911
NSN 5990-01-521-7890
NSN 6145-00-801-4621
NSN 5950-00-369-1593
NSN 5855-01-391-7472
NSN 5950-00-318-3122
NSN 6105-00-189-0515