29 units total. Tech 1 (7 units): Light Gunship, Light Torpedo Bomber, Light Artillery, Light Shield Generator, Light Air Staging Facility, Pressure Mine, and Defense Engineer. Tech 2 (6 units): Mass Storage, Energy Storage, Tactical Bomber, Heavy Wall Section, Proximity Mine, Defense Engineer. Tech 3 (15 units): Heavy Point Defense, Anti-Armor Point Defense, Torpedo Launcher, Shield Wall, Shielded Mass Extractor, Shielded Mass Fabricator, Shielded Power Generator, Nuclear Mine, Heavy Air Transport, Armored Assault Tank, Mobile Anti-Air, Mobile Shield Generator, Decoy Plane, Mobile Strategic Missile Defense, Defense Engineer. Experimental (1 unit): Siege Tank