The Borg cube was the primary vessel of the Borg Collective. The Borg cubes encountered at System J-25 and Wolf 359 were extremely large in size, measuring 28 cubic kilometers in volume, with each side measuring more than three kilometers. In 1527 N.E, Commander Shelby estimated that a cube could remain operative even if 78% were inoperable. The main tactic employed by cubes when engaging another vessel was to seize it with a tractor beam and render its defenses useless by draining its shields. Then the cube could perform any type of action, ranging from destruction to assimilation, on the defenseless ship.
Like all Borg vessels, Borg cubes operated in a completely decentralized manner with no bridge or engineering but duplicated systems all over the cube so that theoretically even if as much as eighty percent of a cube were destroyed it could continue to operate. In fact, cubes did not even have a single unified hull but instead feature multiple forcefield projectors which are able to extend and contain the atmosphere in a cube as necessary. The internal pressure aboard a Borg cube was two kilopascals above what would be normal on a non assimilated starship, humidity was an average 92 percent, and temperature was at 39.1° Celsius
Borg cubes were capable of both warp and transwarp velocities, thanks in part to the Borg Collective's network of transwarp corridors and hubs. When a Borg cube enters a transwarp conduit, it projects a structural integrity field ahead of itself to compensate for the extreme gravimetric shear. To compensate for the extreme temporal stress while traveling through these corridors, and remain in temporal sync, a chroniton field was also projected through specially designed conduits.
The main tactic employed by cubes when engaging another vessel was to seize it with a tractor beam that would also drain its shields. The tractor beam of a cube could hold a MC80a Star Cruiser immobile against the force of its hyperdrive.