SECURITY-class Mjolnir

The MJOLNIR Powered Assault Armor/M variant, also known as the Security armor, is a variation of MJOLNIR Powered Assault Armor developed by Misriah Armory.

Development and history
The MJOLNIR/M variant was first manufactured in the Misriah Armory facility on Mars in 2528, three years after the Mark IV was released in November 2525. Like most MJOLNIR variants, the later model of the Security helmet has been upgraded to be compatible with all current generation MJOLNIR Mark VI variants. The M variant helmet, or a helmet greatly resembling it, is also worn by non-SPARTAN security personnel, such as those assigned to the SPARTAN-IIs' training facilities.

Helmet
Unlock: Get a total of approximately 1000 gamerscore in Halo 3.

The helmet's most noticeable feature is the larger, more prominent "figure-eight" shaped visor which looks almost bug-eyed. It bears resemblance to that of a modern day fighter jet pilot helmet. This helmet is inspired by the protagonist of Marathon, although the mouth is covered. The helmet is large with a small raised section on the forehead in the form of the Marathon logo. Wearing the helmet will also add a small antenna and dial to the right shoulder.
 * Helmet Description: The Mjolnir(m) variant was manufactured at the Misrah Armories Facility on Mars in 2528. It has been upgraded and modified to be compatible with all current-issue armor variants.

The prominent bug-eyed shape has been toned up, and the helmet looks bigger overall.

Shoulder pauldron
Unlock: Officially, the Security shoulders unlock when the player has attained at least 750 Gamerscore points from Halo 3. However, the shoulders are renowned and well-known bugged items.

The shoulder pieces are quite largely rounded, with a section with an upper center, trapezium-shaped arm guard going out the bottom and a rounded section above that. It should be noted that this shoulder permutation is prone to a glitch that may cause you to not unlock them until you have 1000 gamerscore; however, another glitch has occurred that unlocks the Security shoulders before reaching 750 gamerscore points in Halo 3.
 * Shoulders Description: The Mjolnir Mark V(m) Powered Assault Armor was originally manufactured in 2528 and recently upgraded to be compatible with all current-issue armor variants.

The shoulders are less rounded than the Mark V.

Chest
The Security Armor does not have a chest plate, although wearing the helmet will give the player a distinct "antenna and dial" on the right side of the back plate. This may be a reference to the antenna Master Chief had in the pre-Halo: Combat Evolved at the Mac World Trailer.

Helmet
The MJOLNIR(M) variant helmet was manufactured at the Misriah Armories facility on Mars in 2528. Base price: 250,000 cR, General UA/HUL price: 200,000 cR, General CRBN/CNM price: 200,000 cR, Legend
 * Description: All (M) variant helmets have been upgraded to be compatible with all current issue armor systems.
 * Description: Up-armored varient with hardened uplink module for MILINT acquisition.
 * Description: For operations in hazard zones; command network module.

Two upgrades are available for the helmet, the first adds an Up-Armor plate with a Hardened Uplink Module on the right side (UA/HUL), and the second adds a Chemical, Biological, Radiological, and Nuclear Module with a Command Network Module on the left side (CBRN/CNM). The CBRN attachment does not take on its usual gas mask appearance, instead it is the same as the CBRN that is standard on the EOD helmet.

Shoulder
Unlock: 70,000 cR for left shoulder; 275,000 cR for right shoulder, rank of General needed for both.
 * Description: The Supplemental Armor, Pauldron, MJOLNIR(M) variant was originally manufactured in 2528.

The right shoulder is equipped with a Kukri.

Halo 5: Guardians
Unlock: Rare REQ card Available skins: Oppressor and Watchdog Oppressor Unlock: Ultra Rare REQ card Watchdog Unlock: Ultra Rare REQ card
 * Description: Built to Spartan branch requirements for ship and station defense personnel, SECURITY armor seamlessly integrates with Navy networks and security constructs.

Trivia

 * The Halo Encyclopedia erroneously states that the Security armor was manufactured in 2543, as it was manufactured in 2528.
 * The MJOLNIR/M variant is based on that of the protagonist of the Marathon series, who is known only as the "Security Officer". The helmet in particular looks almost identical to the helmet worn by Marathon's protagonist. The Marathon symbol is on the helmet just above the visor.
 * Unlike in Halo 3, the Security helmet does not feature the Marathon symbol in Halo: Reach. This is likely due to intellectual property concerns, as the symbol is also absent from the rest of the game. In Halo 5: Guardians, the Reclaimer symbol appears on the helmet.

List of appearances

 * Halo 3
 * Halo: Blood Line
 * Halo: Reach
 * Halo 5: Guardians