main concentration (of troops)

concentration of troops

simulated concentration (of troops)

main defense area (line) / main defensive position

main tank/ main fuel tank

main gear box / main rotor transmission

main rotor transmission / main gear box

main-rotor head / main-rotor hub

main-rotor hub / main-rotor head

concentration along the key axes

concentration of forces and facilities

killing concentration

lethal concentration

troop concentration

consistent fire concentration

double consistent fire concentration

triple consistent fire concentration

successive barrage / successive concentration

artillery concentration

concentration period

concentration point

vehicle concentration

infantry-armor-artillery-air concentration

oxygen concentration

ozone concentration

concentration of exhaust hydrocarbons

methane concentration

angle of concentration

break up а concentration (of tanks)

concentration and target overlay

concentration area

concentration call

concentration march