5305-01-646-1663 (B1831BH120050L)
NSN 5305-01-646-1663 (NIIN 01-646-1663) is a socket head cap screw in Federal Supply Class 5305, Screws — an externally threaded fastener whose threaded portion is of one nominal diameter. Manufacturer part number B1831BH120050L (American National Standards, CAGE 80204); also referenced as B18.3.1M (American National Standards).
NIIN assigned July 2015; DEMIL A (none required); ESD/EMI-sensitive; unit of issue EA (each), $0.04 gov standard price.