TM 9-2815-202-24P 0001 00 Source Code Application/Explanation PA PB PC PD PE PF PG Stocked items; use the applicable NSN to request/requisition items with these source codes. They are authorized to the category indicated by the code entered in the 3rd position of the SMR code. NOTE Items coded PC are subject to deterioration. KD KF KB Items with these codes are not to be requested/requisitioned individually. They are part of a kit which is authorized to the maintenance category indicated in the 3rd position of the SMR code. The complete kit must be requisitioned and applied. MO - Made at unit/ AVUM Level MF - Made at DS/ AVIM Level MH - Made at GS Level ML - Made at SRA MD - Made at Depot Items with these codes are not to be requested/requisitioned individually. They must be made from bulk material which is identified by the P/N in the DESCRIP- TION AND USABLE ON CODE (UOC) column and listed in the Bulk Mate- rial group work package of the RPSTL. If the item is authorized to you by the 3rd position code of the SMR code, but the source code indicated it is made at a higher level, order the item from the higher level of maintenance. AO - Assembled by unit/ AVUM level AF - Assembled by DS/ AVIM level AH - Assembled by GS level AL - Assembled by SRA AD - Assembled by depot Items with these codes are not to be requested/requisitioned individually. The parts that make up the assembled item must be requisitioned or fabricated and assembled at the level of maintenance indicated by the source code. If the 3rd position code of the SMR code authorizes you to replace the item, but the source code indicates the item is assembled at a higher level, order the item from the higher level of maintenance. XA Do not requisition an “XA" coded item. Order its next higher assembly. (Refer to the NOTE below.) XB If an “XB" item is not available from salvage, order it using the CAGE and P/N. XC Installation drawing, diagram, instruction sheet, field service drawings; identified by the manufacturer's P/N. XD Item is not stocked. Order an “XD” coded item through normal supply chan- nels using the CAGE and P/N given, if no NSN is available. NOTE Cannibalization or controlled exchange, when authorized, may be used as source of supply for items with the above source codes, except for those source coded “XA" or those aircraft support items restricted by requirements of  AR 750-1. Maintenance Code. Maintenance codes tell you the level(s) of maintenance authorized to use and repair support items. The maintenance codes are entered in the third and fourth positions of the SMR Code as follows: 0001 00-2