Figure 1-1. National stock number format.
(2) Items are listed in national item identification number (NIIN) sequence.
Refer to figure 1-2.
Management data is updated monthly.
There is little or no management data on deleted NSNs.
(5) The Interchangeable and Substitute (I&S) History File covers the following
information. Refer to figure 1-3.
(a) Interchangeable item--An item which is equivalent to another item of
similar purpose and can be exchanged without alteration to the item or of adjoining items
except for adjustment.
(b) Substitute item--An item which can be exchanged for another only
under specified conditions and without alterations of the items themselves or of adjoining
items. This term is synonymous with the phrase "one way interchangeability," such as
item B can be interchanged in all applications for item A, but item A cannot be used in all
applications requiring item B.
(c) History cross references--Cross reference information is provided for
which the related NSN/MCN is active or has been inactive for less than two years.