TM10-3930-660-20 f. Column  6,  Federal  Supply  Code  For  Manufacturers  (FSCM).  This  column lists the FSCM for the manufacturer of the tool or test equipment, if available. B-5. Explanation Of Columns In Remarks, Section IV. a. Column 1, Reference Code. This column lists the reference letter code that correlates with the code recorded in the MAC, Column 6, Section II. b. Column  2,  Remarks.  This  column  lists  information  pertinent  to  the maintenance function being performed as indicated in the MAC, Section II. B-4