TM 10-4930-251-12&P 3. EXPLANATION  OF  COLUMNS  IN  THE  REPAIR  PARTS  LIST  AND  SPECIAL  TOOLS  LIST  (Continued). Source     Code AoplicationlExulanation P A PB PC PD PE PF P G I Stock items;  use  the  npplicablc  NSN to I-equisirion/reqtlest items with   these   source  codes.  They    are   authorized     to   the   level indicated  by   the    cods  entered  in  the  3rd  position   of  the  SMR c o d e . NOTE Items  coded  PC  arc   suh~ject     tu  deterioration. KD KF KB I Items  with  these  codes  are  not  to  he   requestedlrcquisitioned individually.  They   are   part  of  a  kit  which  is  authorized  to  the maintenance level indicated in the 3rd position of the SMR code. The  complete   kit  must  be  requisitioned  and    applied. MO-Made  at  unit  level I Items  with  these  codes  are  not  to  he   rcqtlisitionedlreqtlestcd MF-Made  at  DS   level individually.   They   must  he  made    fi-om    hulk   material   which   is MH-Made  at   GS   level identified  by  the  P/N  in  the  DESCRIPTION  AND  UOC  column ML-Made   at   SRA and  listed  in  Bulk  material  group  of  the  RPSTL.  If   the   item  is MD-Made  at   depot authorized to you by the 3rd position code of the SMR code, hut the  source  code  indicates  it  is  made  at  a  higher  level,  order  the item  from  the  higher  level  of  maintenance. AO-Assembled   by unit/AVUM    level AF-Assembled   hy DSlAVIM     level AH-Assembled    by GS   level AL-Assembled   by   SRA 1 AD-Assembled   by   depot XA Items  with  these  codes  are  not  to  he   requested/requisitioned individually.  The  parts  that  make  up  the  assembled  item  must he   requisitioned   or   fabricated   and   assembled   at   the   level   of 1 maintenance  indicated  by  the  source  code.  If  the   3rd  position  of the  SMR code authorizes you to replace the item, hut the  sowce code  indicates  the  item  is  assembled  at   a higher  level,  order  the item  from  the  higher  level  of  maintenance. Do  not  requisition  an  “XA” coded item.  Order  the  next  higher assembly   (refer   to   NOTE   below). XB If an item is not available from salvage, order it using the CAGE Code and  P/N. x  c Installation  drawings,  diagrams,  instruction  sheets,  field  services drawings;   identified   by   manufacturer’s   P/N. X D Item   is   not   stocked,   Order   an   XD-coded   item   through   normal supply   channels   using   the   CAGE   Code   and   P/N   given,   if   no NSN   is   available. NOTE F-2 Cannibalization   or  controlled  exchange,  when  authorized,  may  be  used  as  a  source  of supply for items with the above  source codes except for those items source coded “XA”.