NAS 1352 Rev. 13
SCREW, CAP, SOCKET HEAD, UNDRILLED AND DRILLED, PLAIN AND SELF-LOCKING, ALLOY STEEL, CORROSION-RESISTANT STEEL AND HEAT-RESISTANT STEEL, UNRC-3A AND UNRC-2A
Data Sheet by Aerospace Industries Association - National Aerospace Standard, 05/31/2016