This specification defines the requirements for CRES externally threaded fasteners for use up to 650 ??procured under part numbers listed on drawings which refer to this specification. Drawings may carry notes which modify the requirements of this specification. Receiving contractors may reject any lot which does not conform. Recommendations for improvements or correction of this specification should be directed to NASC representative of a using aerospace company or to National Aerospace Standards Committee@ Aerospace Industries Association@ 1000 Wilson Boulevard@ Suite 1700@ Arlington@ VA 22209.