From Halopedia, the Halo wiki
The SP42 Main Battle Tank (formally Special Purpose-42 Main Battle Tank), commonly known as the Cobra, is a hybrid anti-matériel and anti-fortification vehicle used by the United Nations Space Command. It is manufactured by Misriah Armory.
The SP42 Cobra was first deployed in 2497 during Operation: CHARLEMAGNE. Following this initial deployment the Cobra was presumably used throughout the Insurrection. The SP42 was then used extensively during the Human-Covenant War, particularly during its earlier stages, in which Cobras were frequently used in both offensive and defensive roles.
Despite the Cobra's classification as a main battle tank it is designed to be lightly armored, fast, and maneuverable. Unlike most tanks the SP42 uses six all-terrain wheels that enable impressive mobility even over rough terrain and are protected by pivoting front and rear wheel guards. The two rear wheels are retracted when the vehicle enters lockdown mode.
Unlike most UNSC vehicles the Cobra fills two distinct roles: that of a mobile anti-matériel platform and that of a self-propelled artillery piece. The SP42 MBT is equipped with a pair of turret-mounted M66 30mm light railguns that fire high-density ferrous slugs; these slugs are twice the size of those used by the M68 Gauss cannon and are designed to penetrate enemy armor using sheer kinetic energy. The railguns fire intermittently, not in a single burst, as the energy required to accelerate the slugs to the speeds required to pierce the heaviest armor can only be managed for one of the cannons at a time. Synchronized fire from both railguns can destroy even the most heavily armored tank, with penetration that easily outguns the M808 Main Battle Tank's standard M512 90mm cannon.
In addition to the Cobra's anti-vehicle role the tank can be stabilized upon the ground, "locking down", and deploy an M98 105mm light railgun which fires a conventional explosive shell at supersonic velocities. The explosive and kinetic forces of the shell complement each other to increase the damage inflicted. An M98's shell, when specially outfitted, can penetrate a Shua'ee-pattern Locust's energy shield and destroy the platform; a single shot can likewise disable the shields occasionally outfitted on the Type-26 Wraith and deal minor damage to the hull. Massed fire from several M98s can quickly destroy even a Covenant citadel, a massive structure outfitted with starship-grade armor plating.
The Cobra can be produced at the Vehicle Depot for 350 resources, two population slots, and if the player has a tech level of 2. It has the following upgrades:
List of appearances