Armor Permutations

Armor Permutations are a feature in Halo 3, Halo 3: ODST, and Halo: Reach that lets players customize their multiplayer character's armor to their liking. In Halo 3 and Halo: Reach, this feature allows players to change the helmet, shoulders, and chest armor pieces worn by their multiplayer character. Players also have the option of choosing between being a Spartan or Elite in Halo 2 and Halo 3.

SPARTAN Armor Permutations
There are a wide variety of SPARTAN-II armor permutations in Halo 3. There are eleven helmets, eight shoulder pieces, and eight chest pieces, for a total of 5,632 different SPARTAN-II armor permutation possibilities: one helmet, two shoulder pieces, and one chest piece per permutation, not including the Recon Armor chest piece. It should be noted the Rogue, Mark V, and ODST armor have only helmet pieces, and Security Armor has both helmet and shoulder pieces but no chest permutation. All armor permutations do not show in Campaign

Sangheili Armor Permutations
There is a wide variety of Sangheili armor permutations, with five helmets, five shoulder pieces, and five chest pieces for a total of 625 different Sangheili armor permutations, with one helmet, two shoulder pieces, and one chest piece per permutation.

ODST Permutations
Halo 3: ODST features armor customization, though it is not as complex as Halo 3 ' s. One can play as each member of the squad having their own unique aesthetic Bungie-created armor. Players can choose primary and secondary armor colors, but the armor's main color remains the same (dark gray). Players can also choose whether or not to wear a helmet, unless they are playing as the Rookie or Sergeant Johnson, who cannot remove his helmet and cannot put one on, respectively. Choosing not to wear a helmet does not affect gameplay. Without a helmet, the player still has the same health and stamina, and they can still use VISR mode.

Characters

 * Rookie: Unlocked by default.
 * Dare: Complete the Campaign on Legendary.
 * Buck: Unlock the Tayari Plaza Achievement.
 * Dutch: Unlock the Uplift Reserve Achievement.
 * Romeo: Unlock the NMPD HQ Achievement.
 * Mickey: Unlock the Kizingo Boulevard Achievement.
 * Sergeant Johnson: Came with the pre-order of Halo 3: ODST.

The Armory (Halo: Reach Permutations)
Player customization returns in Halo: Reach, but with far deeper customization options than Halo 3. In Halo 3, unlocking armor permutations involved getting a certain Achievement, or a group of achievements. In Halo: Reach, armor is acquired by purchasing it with "credits" (cR) in The Armory, although some armor permutations may have to be unlocked through Halo: Reach's Achievements, previous purchases, or by reaching a certain rank. Credits are won by winning or finishing games in Campaign, Matchmaking, Firefight, and Forge, or by completing Achievements, getting Commendations, or completing daily and weekly challenges.

In Halo: Reach, there are ten available slots for Spartan armor customization. The ten available slots customizable to Spartans feature the Helmet, Left and Right Shoulder, and the Chest piece, returning from Halo 3. The new slots for customization include Wrist, Utility, Visor Color, Knee Guards, Armor Effect, and Firefight Voice. In addition, the player's helmet can be "upgraded" with various gadgets, known as Helmet Variants. The player will also be able to choose their character's gender, but unlike Halo 3, the Spartan's gender will also be reflected in their body type, instead of just their voice. Additionally, the player's character will also appear in Campaign mode, as Noble Six.

In Halo: Reach, players will no longer be able to use Elites as their default player model in Matchmaking, likely for balancing reasons. Instead, Elites will be used in Matchmaking for the new Spartan-vs-Elite gametypes, and will still be able to use Elites in Custom Games, through a "Preferred Species" setting. Elite armor customization in Halo: Reach has been downgraded from Halo 3 to a complete model swap. Elite armor does not cost additional cR, but instead requires the player to reach a certain rank for certain armor; for example, to obtain the armor of an Ultra Elite, the player must reach the rank of Warrant Officer.

Additionally, the Limited and Legendary Editions of Reach include exclusive armor permutations/effects for your player character. The Limited Edition comes with the "Sangheili Officer" Elite permutation, while the Legendary Edition includes the aforementioned permutation, along with a Spartan "Flaming Head" effect. A redeemable token that gives the player access to the Recon Helmet is bundled with the game to all sales made on the release date, and with all pre-orders outside of North America. However, if the player is equipped with the exclusive flaming helmet effect, the flames will be visible during gameplay but will not be shown in cinematics. As with Halo 3, every armor permutation in Halo: Reach is purely for aesthetic purposes and do not impact gameplay whatsoever.

The last two sets of helmets for Halo: Reach are available through Halo Waypoint only. Using Waypoint will show you how to unlock said armour pieces, which each have a base and two additional styles. The unlocks are linked to overall Halo Career Milestones (linked to universal Halo Gamerscore) and specialist acheivements throughout the Halo game. For example: the Military Police helmet requires the user to have completed Halo: Reach on Normal Difficulty, Stage two of the helmet requires the user to have the A Spoonful of Blamite achievements and Halo 3 Fear the Pink Mist achievement (accompanied by the right Career Milestone award and the base helmet variant).

Trivia

 * There was originally going to be an Arbiter Armor Permutation in Halo 3, but it was taken out before the game ' s release. Bungie, however, did not explain why. Many fans expected it to be released as DLC, but due to the nature of the game that would be impossible.
 * In Halo 3, the neck of an Elite (regardless what Armor Permutation used) is completely immune to any form of damage except for a shot from a charged Plasma Pistol. In addition, the projectile will simply pass through the neck, as though the neck wasn't there, without a blood spatter. This is because both Elites and Spartans have different models.
 * Many people speculate that hitboxes of the Spartans and Elites are shared but this is not true. While Bungie has officially commented on the hitboxes, they regard the size of the hitbox not the arrangement. Hitboxes are an unseen registry mechanic, which fall into the player models. They determine whether or not something has collided with the player. If an Elite is facing profile (sideways), and a shot is fired underneath the head (to where a Spartan's chest would be), the game will not register a hit. The head "hitbox" is forward more on Elites than it is Spartans.
 * Each Elite also has a modified neck, either sleek black or a different model such as scale-like plating at the back of the neck.
 * The armor in Halo 3 was originally planned to be more detailed, with dents and other details in the armor, but this detail was never implemented.
 * Some exclusive Spartan armor permutations for Halo: Reach are available on Halo Waypoint by earning achievements.
 * According to Bungie, once the Lt. Colonel Grade 3 cap in Halo: Reach is lifted, new armors will be unlockable along with the rest of the ranks.