5310-01-353-8191 (S3131)
NSN 5310-01-353-8191 (NIIN 01-353-8191) 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 S3131 (Circor Pumps North America LLC, CAGE 59180); also referenced as SF10907 PIECE 28 (Circor Pumps North America LLC).
NIIN assigned February 1992; DEMIL A (none required); unit of issue EA (each), $7.14 gov standard price.