Additional gear is commonly broken into three main categories known as "lines".
First Line - Close to body gear, worn on body, or in pockets.
Second Line - Working Load equipment, taken off when stationary
Third Line - Sustainment Load equipment, normally in larger packs or vehicles
These lines can be broken down father and sub-categoriezed for more specific purposes. The three lines are blurred and up for mission set orientation, but are commonly reduced to the above generalizations.