MI's, TI's, and SI's prepared in accordance with the general style and format requirements specified herein are intended for use in the operation and maintenance of equipment/weapons systems that are in military service as follows.

An MI gives instructions for uniformally modifying equipment/weapons systems to correct deficiencies in design and to add tactical and technical advantages. An MI's importance in materiel management requires that it be recorded and reported by the serial number of the equipment/weapons system to which it pertains, if possible. An MI includes any instruction that meets the following criteria:

(a) Urgency.

(b) Indispensability to an item or to a system's operation or effectiveness.

(c) Inclusion of guidance on the use of kits or parts which the Marine Corps manages.

A TI disseminates the following:

(a) Professional techniques and maintenance procedures to be applied by designated personnel.

(b) Interim or supplementary technical information that later will be incorporated into a permanent technical manual or other document.

(c) Precautions concerning anticipated or developing technical problems and the instructions to be published to correct them.

(d) Informational technical details (primarily concerning equipment maintenance) that can be more suitably disseminated by an instruction-type technical publication than by another type of publication or document. For example, details on forms to use, special safety measures, serviceability standards, etc.

(e) Testing and inspection procedures.

NOTE: A TI usually does not require the use of parts, special tools, or kits, other than test kits.

An SI disseminates the following (see Figures 13 and 14).

(a) Supply information on equipment acquisition, regulation, and availability. It explains technical aspects of supply matters, but does not provide administrative instructions.

(b) Directs and provides instructions for reporting equipment conditions testing equipment, or requisitioning or disposing of equipment.