The Component Tower was a modular base defense structure that GDI utilized during the Second Tiberium War. The tower itself was just a plug into which a defensive weapon could be installed. This allowed a GDI commander to place a number of empty towers and install the actual defenses later on. The three defense options were:
- Vulcan Cannon Upgrade: Dual 20mm vulcan cannons which are effective against light vehicles and infantry, but lacked range and the penetrating power needed to damage tanks.
- RPG Upgrade: Fires explosive projectiles which are effective against most vehicles as well as infantry.
- SAM Upgrade: Fires anti-aircraft missiles at hostile aircraft.
Also note worthy is the fact that component towers themselves could be deployed as part of a wall, so it opened up new defensive options. Any upgrade placed upon a damaged component tower will also have a side effect of fully repair the tower's armor. In addition, selling a component tower that is connected to a wall will damage all walls attached to the sold structure.