MIL STD- Military Specification and Associated Documents, Preparation of

4.1 General
This section covers general aspects of style, format, and general requirements for preparing a six-section specification. See figure 1 for a checklist that may be used as a guide, and figure 2 for a list of standard paragraphs that are required or required when applicable.

4.2 Coverage
A specification shall be prepared to describe essential technical requirements for purchasing materiel (see 6.30). Similar items shall be covered in a single specification to the maximum extent practical. Specifications shall describe the item in a manner which will encourage maximum competition. Insofar as practicable, requirements shall be in terms of performance. Requirements shall not be specified to a degree of unnecessary exactness or restrictiveness, but shall be detailed only to the degree necessary to ensure the acquisition of items adequate for the purpose to be covered. When the other than form, fit, and function requirements are necessary to ensure specify details of design such as dimensions, materials, compositions, and physical and chemical requirements to the extent necessary to ensure interchangeability of replacement parts.