120mm cannons are all-purpose cannons developed by the Terran Dominion for the A.R.E.S. warbot. They deal moderate explosive damage to all forms of hostiles. During the raid on the Castanar installation by Raynor's Raiders, Jim Raynor encountered an ARES warbot with the ability to be outfitted with 120mm cannons.
References[]
Blizzard Entertainment. StarCraft II: Wings of Liberty. (Activision Blizzard). PC. Mission: Wings of Liberty, Piercing the Shroud (in English). 2010-07-27.