Energy projector
From Halopedia, the Halo wiki
Template:FOF-1 The Energy Projector was a Covenant starship weapon.
Operations
The weapon fired a thin,compared to the ship, near-lightspeed beam of extremely energetic particles. It was possible to determine when it was about to fire because it typically generated a detectable radiation spike before firing. The beam has an effective range of about 100,000 kilometers, longer even than that of a UNSC Super Orbital Magnetic Accelerator Cannon. The long range allowed a ship armed with this weapon to 'snipe' targets.
It also seems to be comprised of pure energy or very low-mass particles because they do not alter an objects trajectory as it was fired at a MAC round and the kinetic energy was unchanged. In fact it could have been made more powerful because of the massive amount of heat it absorbed.
Effects
The beam was able to take down the shields of a Covenant frigate or destroyer with a single hit.
Against UNSC ships, the weapon was able to pierce dozens of Titanium-A armor layers with ease. Therefore, a single hit could potentially disable or destroy vital systems, such as MAC cannon or engines, rendering the ship useless for combat.
The beam is similar to the Covenant sniper rifle in how and what it fires although on a much larger scale. It is also speculated that the beam can be focused to varying degrees. On Reach it burned a hole through many many meters of earth. However in space they can be focused to a smaller, therefore more powerful beam generally used to decimate enemy ships from afar. It also seems to drain all or most of the energy in a Covenant ship for a brief period unless the ship is massive enough to supply the power without to much of a drain.
Distribution
According to Fred-104, only the "big ships have them." Ships of the Template:ShipClass and the Covenant Supercruiser were known to wield this weapon. Other large ship classes, such as Covenant Assault Carrier or the Covenant Supercarrier, may have it as well.