Armor customization

"Armor Permutations" are a feature in Halo 3, allowing the player to aesthetically customize their multiplayer character.

Introduction
Armor Permutation allows a player to customize his/her multiplayer character as either a UNSC SPARTAN-II or a Covenant Elite, and change between different helmets, shoulder pads, chest armor, and detailed colors (primary color, secondary color, and armor detail). All permutations are aesthetic only and do not change actual gameplay.

They were originally discovered in the Halo 3 Beta hexadecimal codes by modders and were later confirmed to provide high levels of player customization by GamePro's June magazine issue. Calculated together, there are 187,947,000 combinations for the player to choose from.

Armor Permutations are unlocked by achievements in either the Campaign or multiplayer modes of Halo 3.

SPARTAN Armor Permutations
There are a wide variety of SPARTAN II armor permutations, with 11 helmets, 8 shoulder pieces, and 8 chest pieces for a total of 6,144 different SPARTAN armor permutation combinations: one helmet, two shoulder pieces, and chest piece per permutation.

Helmets

 * Mark VI: Default Unlocked.
 * CQB: Default Unlocked.
 * EVA: Complete Campaign on Normal, Heroic, or Legendary difficulty.
 * EOD: Complete Campaign on Legendary difficulty.
 * Hayabusa: Collect all 13 Gold and Silver skulls.
 * Security: Get all[49] Achievements in Halo 3.
 * Scout: Unlock the Used Car Salesman achievement.
 * ODST: Unlock the Spartan Graduate achievement.
 * Mark V: Unlock the UNSC Spartan achievement.
 * Rogue: Unlock the Spartan Officer achievement.
 * Recon: Bungie Employees, winners of tournaments/double exp weekends, and those that impress Bungie in any other way.
 * Flaming Helmet: Bungie Employees only. Rather than the actual helmet generating the effect, it is a unique chest piece that can reproduce the effect on any helmet. Bungie did state that they may release details on how to get this permutation in their podcast.

Shoulder Pieces

 * Mark VI: Default Unlocked.
 * CQB: Default Unlocked.
 * EVA: Complete The Ark on Normal, Heroic, or Legendary difficulty.


 * EOD: Complete The Ark on Legendary difficulty.
 * Hayabusa: Collect at least 9 skulls.
 * Security: Get 700-800 of 1000 gamerscore on Halo 3. Due to inconsistency, this armor permutation is not always given at 750, whereas there are some reports that the Security Shoulders need a minimum of 800 gamerscore, but the official guide to Halo 3 lists the requirements as 750. Sometimes it is unlocked even before that. It may appear and/or disappear temporarily from the armor list. But
 * Scout: Unlock the Mongoose Mowdown achievement. Don't be tricked by Piggyback's false listing in their guide-it says you must achieve the Used Car Salsesman achievement to get this perm.
 * Recon: Bungie Employees, winners of tournaments/double exp weekends, and those that impress Bungie in other ways.

Chest Armor

 * Mark VI: Default Unlocked.
 * CQB: Default Unlocked.
 * EVA: Complete Tsavo Highway on Normal, Heroic, or Legendary difficulty.
 * Hayabusa: Collect at least 5 skulls.
 * Katana (Add-On): Get all achievements in Halo 3. (''Note, Katana is a sword on the back of your armor . Not a chest plate.)
 * EOD: Complete Tsavo Highway on Legendary difficulty.
 * Scout: Unlock the Too Close to the Sun Achievement.
 * Recon: Bungie Employees, winners of tournaments/double exp weekends, and those that impress Bungie in any other way( please note, it is beleived that only four non-Bungie players have access to this armor as well as Flaming Head).
 * Flaming Helmet Chest Piece: Bungie Employees only. Bungie did state that they may release details on how to obtain this permutation in their podcast.

Elite Armor Permutations
There are a wide variety of Elite armor permutations, with 5 helmets, 5 shoulder pieces, and 5 chest pieces for a total of 625 different Elite armor permutation combinations: one helmet, two shoulder pieces, and chest piece per permutation. Some players think that the Sangheili players have been shortchanged when it comes to armor variants.

Helmets

 * Combat: Default Unlocked.
 * Assault: Default Unlocked.
 * Flight: Complete Campaign on Heroic or Legendary difficulty setting.
 * Ascetic: Unlock the Steppin' Razor achievement.
 * Commando: Unlock the Overkill achievement.

Shoulder Armor

 * Combat: Default Unlocked.
 * Assault: Default Unlocked.
 * Flight: Complete The Ark on Heroic or Legendary difficulty.
 * Ascetic: Unlock the Overkill achievement.
 * Commando: Unlocked automatically after Auto Update 1 was applied on February 19, 2008.

Body Armor

 * Combat: Default Unlocked.
 * Assault: Default Unlocked.
 * Flight: Complete Tsavo Highway on Heroic or Legendary difficulty.
 * Ascetic: Unlock the Up Close and Personal achievement.
 * Commando: Unlock the Triple Kill achievement.

Unlocking Permutations
Note: The Arbiter's armor cannot be unlocked. Note: A variant of the EOD chest is available only to Bungie Employees, and is known as the Fire permutation. In addition to having the same look as the EOD chest, it causes the wearer's head to appear on fire. 300px All of the armor permutations.

Trivia
the hayabusa spartan armor permutation is featured as the armor of the main character of the popular halo 3 machinima Deus Ex Machina