TM 10-3930-671-24 maintenance   functions   authorized   in   the   maintenance   allocation   chart.      The   symbol   designations   for   the   various maintenance levels are as follows: C Operator or Crew L Specialized Repair Activity (SRA)⁵ O Organizational Maintenance H General Support Maintenance F Direct Support. D Depot Maintenance e. Column (5), Tools and Equipment.  Column 5 specifies, by code, those common tool sets (not individual tools) and special tools, TMDE, and support equipment required to perform the designated function. f. Column (6), Remarks.  This column shall, when applicable, contain a letter code, in alphabetic order, which shall be keyed to the remarks contained in Section IV. ⁵Specialized Repair Activity (SRA) - This maintenance level is not included in Section II, Column (4), of the Maintenance Allocation Chart.  Functions to this level of maintenance are identified by a work-time figure in the ’HW column of Section II, Column (4), and an associated Reference Code is used in Remarks, Column (6). This code is keyed to Section IV, Remarks, and the SRA complete repair application is explained there. B-4. EXPLANATION OF COLUMNS IN TOOLS AND TEST EQUIPMENT REQUIREMENTS, SECTION III. a. Column (1), Reference Code.  The tool and  test  equipment  reference  code  correlates  with  a  code  used  in  the MAC, Section II, Column (5). b. Column (2), Maintenance Level.  The lowest level of maintenance authorized to use the tool or test equipment. c. Column (3), Nomenclature.  Name or identification of the tool or test equipment. d. Column (4), Tool Kit The national stock number of the tool or test equipment. B-3