M52B body armor

The M52B Body Armor is an armored protective vest worn by the members of the UNSC Marine Corps, and a part of the UNSC Marine BDU. It is usually worn with the CH252 Helmet for greater ballistic protection.

The armor was first seen in late 2552, and it is likely that it was first issued in the same year, hence the designation "M52".

Description
Worn by UNSC Marines, the M52B Body Armor consists of olive-green armor plating over combat fatigues. The body armor is worn like a vest over the torso, and seemingly consists of two parts. A number of ammunition pockets, holsters, and other features can be attached to the armor.

The M52B armor is extremely resilient towards traditional ballistic weaponry. This being said it can be easily damaged by plasma weaponry. The armor consists of several layers, some of which include a ballistic shock-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 performance 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.

Usage
The M52B armor saw use mainly during the opening stages of the Battle of Earth, such as in the Battle of Mombasa. It was later used during the Battle of Installation 05 and the Battle of High Charity. Numerous crates containing the M52B armor were shipped to Delta Halo with the. Similar crates could be found later in the UNSC base Crow's Nest and numerous UNSC outposts in the region surrounding it.

What appears to be a different version of the armor saw use around the same time. It is unknown if this is a separate armor altogether, a variant of the M52B, or simply an aesthetic upgrade.

It features a slightly bulkier chest armor, with a black ballistic vest under it, which extends partially to the arms with the shoulder pads attached to it, unlike the previous version. The stomach has no metallic armor plating like the earlier variant, but it, as well as the groin are protected by a plates of lighter armor. The lower back has no additional armor plating other than the ballistic vest.

It was also used in the Battle of Mombasa, as well as most of the Battle of Earth after the Mombasa Slipspace Event, including the Battle of Voi. The Marines also used it later in the Battle of Installation 00.

Trivia

 * It's unknown if the changes from Halo 2 to Halo 3 and Halo 3: ODST should be considered canon or simply an aesthetic change. In Halo 3: ODST, the Marines in New Mombasa wear the Halo 3 version, despite the events taking place during Halo 2. It is possible that the Marines stationed in different parts of the city wore different types of armor, as the locations of Halo 2 are never visited in Halo 3: ODST. However, visual changes without a canon explanation are fairly common.
 * The armor is still labeled as M52B on containers in Halo 3, with the image of the Halo 2 variant of the armor.
 * Nicknames for the body armor include: BA, BO, Gear, Shell, and Armor.