TM 1-1500-204-23-6 CHAPTER 7 CONSUMABLE MATERIALS 7-1. General. The consumable or expendable supplies In the listing in this chapter are to be used only as indicated in the applicable maintenance manual. Many of these supplies are not compatible with one another.  If used wrong or mixed improperly, they could cause a volatile or undesireable reaction. For these reasons, substitution will be made only with the approval of AVSCOM Engineering. 7-2.  Consumable  Items.  Consumable  items  are  those  Items  which  generally  fall  into  one  or  more  of  the  following categories: · One-time use · Lose identity · Inexpensive · Disposable Some consumable items have a limited useful life. This is termed shelf life An explanation of shelf life codes is shown in table 7-1 See table 7-2 for an explanation of the Essentiality Code (EC). 7-3. Consumable Items List.  The consumable items list In this chapter is provided in two parts. Part 1 is in part number sequence,  while  Part  2  is  in  nomenclature  sequence.  The  column  titles  found  on  these  listings  are  described  in  the following paragraphs. a. Consumable Items Part 1. The column heads in the part 1 listing, from left to right, are as follows: · P/N part number · FSCM federal supply code for maintenance · NOMENCLATURE self-explanatory · UM unit of measure · EC essentiality code · SL shelf life code · ADDITIONAL INFO self-explanatory · NSN national stock number b. Consumable Items Part 2. The column heads in the part 2 listing, from left to right, are as follows: · NOMENCLATURE self-explanatory · P/N part number · FSCM federal supply code for maintenance · UM unit of measure · EC essentiality code · SL shelf life code · ADDITIONAL INFO self-explanatory · NSN national stock number 7-1