M52B body armor

The M52B Body Armor is the standard issue protective body armor of the UNSC Marine Corps. It is usually worn with the CH252 Helmet for greater ballistic protection. Unlike the radically more advanced MJOLNIR Armor worn by the Spartan-II soldiers, the M52B armor does not include a dynamic recharging energy shield, providing far inferior protection against directed-energy and projectile weapons.

Description
Worn by UNSC Marines, the M52B Body Armor consists of armor plating over combat fatigues, and includes a number of ammunition pockets, holsters, and other features. There seem to be a number of varieties. It is unknown if the changes between the games are instances of different armor models altogether, or if the changes are simply aesthetic.

Halo: Combat Evolved
The equipment used during the Battle of Installation 04 involved gray fatigues, with greyish brown armor plating covering most of the body.

Halo 2
The marine armor used during the First Battle of Earth was olive green, with a woodland camo-covered battledress. It had less armor pieces than the variant seen in the first game. .

Halo 3
During the Second Battle of Earth, the armor used by the UNSC Marine Corps was fairly similar to the one in Halo 2, with several minor changes. The fatigues now had an urban camouflage, while the armor itself retained its olive-green color. The armor is still labeled as M52B on containers in Halo 3. .

Resilience
The M52B armor is extremely resilient towards traditional ballistic weaponry. This being said it is fazed easily by plasma weaponry. The armor consists of several layers, some of which include a ballistic recoil-absorbing gel layer and a heat reduction gel layer to help reduce velocity and felt shock from ballistics, shrapnel, and explosives as well as reducing the burn caused by plasma once it reaches flesh. This heat reduction layer also reduces the chance of the plasma penetrating by counter-acting and dissipating the heat, effectively disarming the blast. While this armor protects the wearer from harm caused by weaponry it also has temperature-regulation units integrated into it to keep the wearer at optimum comfortability while eliminating the need to change depending on the environment. This also reduces the enemies ability to track soldiers via thermal energy as it is mostly hidden beneath this armor.