General support maintenance can remove, replace, and use the
Specialized repair activity can remove, replace, and use the item.
Depot can remove, replace, and use the item.
Fourth Position. The maintenance code entered in the fourth position tells
you whether or not the item is to be repaired and identifies the lowest
maintenance level with the capability to do complete repair (perform all
authorized repair functions).
Some limited repair may be done on the item at a lower
level of maintenance, if authorized by the Maintenance
Allocation Chart (MAC) and SMR codes.