SAM is the English abbreviation for: Surface to Air Missile
That's the name of our basic defence rocket launchers which automatically defend your base from the enemy, even when you are offline.
If all your SAMs are destroyed by the enemy, your base is lost and can be captured by the enemy.
IMPORTANT: Please note that the range of the SAM is defined by a CIRCLE and not by a square area, here is an example to understand what this means and in which direction it "looks" as if it will continue shooting. The range always starts from the gate of the base.