5310-01-500-4904 (2126)
NSN 5310-01-500-4904 (NIIN 01-500-4904) is a hexagon plain nut in Federal Supply Class 5310, Nuts And Washers — a nut, flat on top and bottom having 6 flat sides. Manufacturer part number 2126; also referenced as 2126 2634-128 (Macgregor USA Inc.).
NIIN assigned August 2002; DEMIL A (none required); ESD/EMI-sensitive; unit of issue EA (each), $1.36 gov standard price.