Laser Defense is a stationary defense fortification. It includes a cannon to defend the territory from attackers. It is the most basic fortification and has the advantage of being cheap, quickly constructed and does not require energy upkeep in the first game.
Laser Defenses are self-contained, do not require workforce to operate. They also run on batteries which are plenty enough to last for whole battles.
The firepower of a Laser Defense is comparable to a Laser Cannon.