One of these fundamentals is the Einheit (unit) principle, which provides that any given arm or service will develop a number of standard unit groups, each with standard organization, leadership, training, and equipment. The unit group is an organic entity, capable of operating independently and self-sufficient both for tactical and administrative purposes. Within a given branch or service, each basic type of unit group will represent a different combination of the various components (or weapons) of that branch or service. In AA organization the unit groups are ordinarily battalions, and the types (heavy, mixed, light, etc.) differ in organic composition with respect to their respective weapons (light and/or heavy guns, searchlights, etc.).

The Einheit principle of organization has several advantages. Obviously the supply and replacement of equipment can be more readily geared to a few standard types of units. The training and tactical employment of a given type of unit can be standardized, and directed with uniformity. Above all, the existence of these basic type-units, each so composed as to serve a different function, permits easy organization of any desired type of larger unit. In the AA branch, for example, regiments are formed by combining any desired number of the different basic units. And the Einheit system is excellently designed to facilitate the construction of task forces, made up of different amounts of necessary arms and services, in terms of the basic units of each arm or service required for a given mission.