The 120mm cannon is developed from the smaller 105mm cannon, and has four ammunition upgrades that increase its firepower and one weapon upgrade which adds an additional cannon. For all it's improvements over the 105mm cannon, it requires a Heavy weapon slot, meaning it can only be mounted on certain units. However, and most importantly, this is not the 120mm cannon's only note, as it also has the ability to mount a smaller weapon. The following weapons can be mounted on the 120mm cannon when it is in turn mounted on a unit:
It can be mounted on the following units:
While mounted on the ESS 200, the 120mm cannon becomes the 120mm Artillery, with massively increased range. Additionally, it can be mounted on any building with a Heavy weapon hardpoint, but the building-mounted version cannot mount a secondary weapon. While there are historical documents that indicate otherwise, the 120mm Cannon cannot be fitted onto TT series vehicles.