Pulse laser turret

From Halopedia, the Halo wiki

The Pulse Laser turret is a very powerful Covenant starship weapon. It is used in most combat situations. Before the weapon fires, it must first charge, during the charge a sphere of light/energy forms at/around the charging weapon, after the charge that takes mere seconds it will fire , The pulse laser turret seems to be the most common covenant ship mounted weapon as every covenant ship encountered so far has been equiped with then.

The weapon is said to have reduced the UNSC frigate commonwealth's armour in sections three and four to 25% which would mean (as frigates are known to have 60cm thick armour) that a pulse laser hit is capable of melting through 45cm of titanium A battleplate in mere seconds, also there is said to be a hull breach in secton three. This means that pulse lasers pose a serious threat to UNSC frigates (and presumably smaller and lighter armoured UNSC ships) as it only takes one hit to melt through parts of it's armour however bigger UNSC ships which have thicker armour would have to take multiple hits to get the same results

The beam itself is stated to be blue in color in chapter twelve of Halo: the fall of reach, also what are presumed to pulse laser are seen destroying escape pods in the first campaign level of halo: combat evolved and these too are blue in color.