PERSONAL  FOR  messages  are  used  only by  and  addressed  only  to  Navy  commands. Standard  Subject  Identification  Code The  SSIC  identifies  the  subject  matter  of the  message. The  SSIC  is  preceded  and followed  by  two  slant  signs;  as,  UNCLAS  E F  T  O  FOUO  //N02000//.  The  SSIC  always contains   five   digits   corresponding   to   the particular   subject   matter,   preceded   by   the letter  N.  With  few  exceptions,  an  SSIC  is required   on   all   naval   messages. Those messages without SSICs are normally returned to  the  drafter.  Many  automated  systems  route message  traffic  by  the  SSIC. SSICs  are  contained  in  Department  of  the Navy   File   Maintenance   Procedures   and Standard   Subject   ldentification   Codes, SECNAVINST  5210.11. Passing and Delivery Instructions The  majority  of  naval  automated  message processing   systems   rely   on   specific   elements at  the  beginning  of  the  text.  These  elements may  be  flag  words,  code  words,  subject  lines, and   outgoing/incoming   message   references. These  elements  serve  as  guides  and  assist  the automated   internal   routing   of   messages. Special  delivery  instructions,  such  as  FOR, FROM,   PASS   TO ,  are  additional means   of   indicating   that   the   text   of   the message   is   to   receive   the   attention   of   the indicated individual   or office without necessarily  limiting  the  normal  distribution. Special   delivery   instructions,   when   used, follow  the  SSIC.  These  instructions  are  used for  exceptional  cases  not  covered  by  use  of office   codes   in   the   address. Passing instructions  must  not  be  separated  into  an individual  paragraph  of  the  text.  They  should follow  the  SSIC  and  can  continue  on  the  line immediately   following   the   classification   and SSIC. Subject Line The   subject   line   indicates   the   basic contents  of  the  message. Internal   message routers and   Navy automated    message processing   systems   key   on   the   subject   to determine internal   message distribution. Therefore,    messages    containing    similar information  should  be  assigned  a  standard subject whenever possible to facilitate message identification  and  internal  distribution. The  subject  line  of  a  message  begins  at  the left-hand  margin  immediately  following  the classification  line  with  the  characters  SUBJ. Reference  Lines Reference  lines  are  used  to  avoid  repeating lengthy  quotations  or  references  within  the text  of  a  message. A  reference  may  be  any message,   document,   correspondence,   or telephone  conversation  that  is  pertinent  to  the message.  When  a  reference  is  referred  to  in the  text,  it  would  be  called  REF  (A),  REF (B),  or  REF  (C),  as  applicable. Indenting The  classification,  subject,  and  reference set   lines   will   always   begin   at   the   left-hand margin. Textual  material  may  be  indented  a maximum  of  20  spaces  for  clarity. Remarks The  RMKS  (remarks)  set  begins  the  actual text. The   message   may   contain   several subjects  or  several  aspects  of  one  subject.  For this   reason,   textual   material   is   divided   into paragraphs  and  subparagraphs  (numbered  and lettered   consecutively). Classification  and  Paragraph  Markings When  a  message  is  classified,  the  subject line,   all   paragraphs,   and   subparagraphs   are marked   with   the   appropriate   classification symbol.  This  eliminates  any  doubt  in  the 3-25