Class Mod (Borderlands)

Class Mods, or COMs (short for Class Modification Units, or Class Optimization Modules), are influential items in Borderlands, first usable after characters have reached level 15. They are class specific upgrades that provide bonuses to abilities of the character - or even the entire team - by offering a wide variety of bonuses such as amplifying a character's damage, healing, increasing character health or shield capacity, reducing reload times, increasing skill ranks, etc.

Gameplay
Class mod skill bonuses do stack, even if a specific skill is maxed (5/5), up to a total maximum of 9 ranks in any skill. A skill bonus however will not function unless the character has at least 1 point invested in the specified skill.

Class mods can be obtained in several ways throughout the game.
 * They can be bought from Medical Vending Machines.
 * Found in many of the lootable objects such as: Chests, skag piles or lockers.
 * As a reward from completing a mission.
 * Dropped by certain enemies when they are killed.
 * Sixteen new class mods are available to players who have installed The Secret Armory of General Knoxx; Specter, Ogre, Marine, Truxican Wrestler and the twelve manufacturer Loyalty mods. These are available only from specific enemies and quests inside The Secret Armory of General Knoxx DLC.

Manufacturer
Class mods come in three levels of rarity; green, blue and purple. A particular class mod may be produced by two different manufacturers despite the mod having the same modifiers. For example, the Bombardier class mod for Berserkers is made by both Dahl and Tediore.

Class mods are built with three primary parts: left side, body, right side. The body is standardized by class subtype; berserker, bombardier, etc. Class mods are made with one of three materials. The material used determines which effect bonus the mod will have and has no effect on the skill bonuses. Material #1 gives the default effect only. Material #2 gives the default effect and effect #2. Material #3 gives the default effect and effect #3.

Most class mods have six possible modifiers; three effects and three skill bonuses. A COM can have a maximum of five of these modifiers due to the material #2 effect and material #3 effect being mutually exclusive. Additionally, for the skill bonuses, only one can be the maximum value of +4.

Nomenclature
The name of a Class Mod appears different in the Inventory list than on its Item Card; in the inventory list, the mod has an additional number designator at the beginning of the name. The number designator is a two, or three-digit number. The numeric designation (such as 14, 230, 560, etc) partially determines the quality of the class mods and directly correlates to the level of the mod's bonuses and effects. The number is unaffected by the COM title, the manufacturer, and material grade. A mod's required character level also determines the quality of the effect bonus.

The number code indicates two things: Thus, the best possible mods (for that required level) would have the code 660.
 * The tens digit (or ones digit if the number only has two digits) represents the left-side piece of the COM and determines the quality of the skill bonuses, where 1 is the worst and 6 is the best. From best to worst: 6 gives a 4/3/3; a 5 gives 3/2/2; 4 gives 4/3; 3 gives 3/3; 2 gives just a single 3; and 1 only gives a single 2. The higher skill in a set or the skill(s) left out of a low quality mod are chosen at random, meaning two 660 mods can be identical except the +4 skill boost.
 * The hundreds digit (or tens in a two digit number) represents the right-side piece of the COM and determines the quality of the effect bonuses, but has no bearing on which one; that is solely based on material type: 600 is the best. For the highest quality mods, this is represented by the 100s digit in the mod name. Each mod has its own minimums and maximums. A 600 series mod will have the highest effect bonus for its level; a 500 series mod will have less for its level; and so on.

For a given quality of Class Mod, the item level further defines the effect bonuses, the most significant of which being a step up in skill boost at level 29. The effect bonuses for a Vladof 660 Rifleman Class Mod are tabulated below:

Variety
Each class has eleven sub-classes of mods. Each mod is geared towards a specific branch of the skill tree. As such, the bearer will only receive the full benefit of the mod used if the skills are matched to the mods. Some class mods are better than others but have one perk that makes them stand out, such as ammunition regeneration or increased accuracy. Keep in mind that only one class mod can be equipped at once. Of the original seven, four are geared to solo play and three geared to team play. The Secret Armory DLC adds four mods for each class, three of which are Loyalty mods.

Loyalty Mods
The third DLC adds three new Class Mods for each class specialized on a consumer loyalty concept. The mods boost only the effects of the item of the same company as the mod itself (ie. +Shield Capacity only increases that of the same manufacturer's shield, and +Weapon Damage to same company's weapon). If a character has a Hyperion Loyalty Mod like the Sharpshooter of Hyperion, and uses a Hyperion weapon, he gets an award of bonus weapon damage. The same applies for Anshin that boosts Shield Capacity or Regeneration Rate. This very helpful class mod also increases the chances of finding more weapons from that manufacturer. A problem once came up with these class mods: a player equipped the loyalty mod in an online game, and after switching to a single player or split-screen game the mod would disappear. This error was fixed in a later patch. See Notes below.

Siren

 * Note that the Eridian Warrior does not spawn any 2/3 material effects. +42% Weapon Magazine Size or +35% Weapon Damage can be Modded.

Solo

 * Firefly Mod focuses on the use of Incendiary weapons. It is good against unshielded, fleshy enemies.
 * Mercenary Mod focuses on the use of SMGs. It increases damage and boosts three key skills. Ammo regeneration is helpful.
 * PlagueBearer Mod focuses on the use of Corrosive weapons. It is good against armored enemies and boosts to Mind Games and Inner Glow add to survivability.
 * Specter Mods focus on the effectiveness of sniper rifles, affects critical hit damage, sniper rifle damage, sniper accuracy, bullet velocity and sniper ammunition regeneration. Note that accuracy and ammo regeneration modifiers will not fit on the item card if 3 skill attributes and +100% critical damage are present on the COM.
 * Tempest Mod focuses on the use of Shock weapons. It is useful against guardians and other well-shielded enemies.

Team

 * Catalyst Mod focuses on reducing team cooldowns, and boosts the Siren's On Kill skills. It can also help find rare items, or improve shield regeneration rates.


 * Note: Specific strategies for Catalyst cool down are on the talk page.


 * Note: To explore the discussion of whether Catalyst +2 Team Find Rare Items affects chests, visit +2 Team Find Rare Items Experiment


 * Defender Mod increases team and personal survivability, in particular shield capacity and Elemental resistance.
 * Tormentor Mods help teams using elemental weapons, improving chances to cause Elemental Effects and damage.

Solo

 * Commando Mod focuses on the use of shotguns and abilities that compliment the use thereof. It is recommended for close-range encounters or fights against very large enemies.
 * Heavy Gunner Mod lets a properly built Soldier unleash a devastating storm of weapons fire once they get started. It is a good mod for close-range or extended fights. It also allows great use from weapons which suffer from small magazine sizes such as Eridian Weapons.
 * Rifleman Mod focus on soldiers using combat rifles. It is very useful for players who favor machine guns and combat rifles. Ammo regeneration is useful for players intending to keep using the machine gun.
 * Shock Trooper Mod focuses on electrical damage and grenade attacks, as well as boosted health. It is effective against guardians.

Team

 * Leader Mod focuses around boosting team experience gains, action skill cooldowns, and the rate at which the Scorpio turret can be deployed. It can also boost the Soldier's own defensive abilities. Best used for teams not yet at the level cap, and/or to assist in maxing out weapon proficiencies.
 * Support Gunner Mod pack is an excellent solo and team mod thanks to ammunition regeneration and increased team magazine sizes. They are very useful to teams using ammo-hogging weapons.
 * Tactician Mods are good for supporting soldiers, and can also increase the Soldier's own survivability considerably. The defensive benefits are most pronounced for teams who are mostly equipping fast charging Anshin shields.
 * Marine Mods allow soldiers to effectively use launchers and grenades, and can heal team members very easily during firefights through the use of the splash from explosives, even damaging enemies and healing teammates simultaneously.

Solo

 * Berserker Mod focuses on maximizing the effectiveness of Brick's Berserk skill, providing the highest benefits to damage output with Brick's fists, and survivability through health recovery while Berserk. It is recommended for players who prefer using Berserk to defeat tough enemies.
 * Blast Master Mod adds extra explosive impact to Brick's explosive weapons as well as the skills that increase ranged weapon rate of fire and damage output. Recommended for use in conjunction with a suite of weapons that deal explosive elemental damage, including but not limited to rocket launchers.
 * Bombardier Mod focuses on the blaster skill tree and Brick's ability to fire rockets. It can also improve launchers' fire rate or provide rocket ammo regeneration. Provides sustained ability to provide continous fire support with rocket launchers.
 * Ogre Mod focuses on the use of shotguns and abilities that complement the use thereof. Recommended for close-range encounters or fights against very large enemies.
 * Titan Mod focuses on keeping Brick alive for as long as possible. It is a very effective mod for sustainably tanking vast amounts of incoming damage through proper shield management, particularly in solo situations.

Team

 * Centurion Mod focuses on Brick's ability to act as a tank for the team and keep himself and other players alive. If sheer personal survivability is more appropriate then a Titan mod becomes the preferred choice.
 * Skirmisher Mod focuses on close combat. Notably contains a skill boost to allow near-constant Berserk mode. It is recommended for players who use Berserk as a main attack method, and greatly benefits teams with more than one Berserker.
 * Warmonger Mod focuses on the damage that Brick and his team can deal. It is most effective against larger groups of weaker enemies due to on-kill skill boosts.

Solo

 * Assassin Mods focus on the effectiveness of corrosive damage. They improve effectiveness with Corrosive weapons, melee damage and Corrosive Resistance.
 * Gunfighter Mods focus on the effectiveness of Jakobs Pistols, for pure strength without Elements. This mod boosts Accuracy, Critical Damage and the number of bullets fired.
 * Gunslinger Mods focus on the effectiveness of pistols. They affect pistol fire rate, damage, ammunition regeneration and accuracy. Oddly, they can also increase the magazine size for sniper rifles. This was likely meant to be the Hair Trigger skill instead, which increases pistol magazine size.
 * Hunter Mods focus on the effectiveness of Bloodwing. They affect Bloodwing's damage, cooldown, and number of item drops.
 * Peace Keeper focus on the survival aspect of the Hunter with an Anshin Shield. It boosts shield capacity, health regeneration and the ability to bypass shields with Trespass.
 * Sharpshooter focuses on Accuracy and Weapon damage via Hyperion Weapons. It boosts Weapon damage, Critical Hit damage and may improve Grenade damage or Shield Recharge Delay.
 * Sniper Mods focus on the effectiveness of Sniper Rifles. They affect critical hit damage, sniper rifle damage, Bloodwing's cooldown via sniper shots, sniper accuracy and sniper ammunition regeneration. Note that the secondary effect will not fit on the item card if 3 skill attributes and a +100% critical damage is present on the COM. The COM may still have a secondary effect, but to discover it requires experimenting.
 * Truxican Wrestler Mods focus on the effectiveness of melee combat. They affect melee damage and maximum health.

Team

 * Ranger Mods focus on the effectiveness of Bloodwing and Accuracy. It does so by affecting accuracy, critical hit damage, and Bloodwing's cooldowns and ability to attack multiple targets.
 * Note: A x60 Ranger Mod with +4 Predator skill will allow a one second Bloodwing recharge if the Predator skill is maxed. Having the Out for Blood skill maxed is a great combo with this to keep your health up.


 * Scavenger Mods focus on the effectiveness of looting. They do so by affecting the amount of items found, their rarity and the bearer's health return. It can also affect health regeneration.
 * Note: To explore the discussion of whether Scavenger +2 Team Find Rare Items affects chests visit +2 Team Find Rare Items Experiment


 * Survivor Mods focus on the effectiveness of team and personal survivability. It does so by affecting team health regeneration, items dropped by enemies and reload speeds. It can also affect team damage.

Trivia
The Soldier's Shock Trooper mod could be a reference to Gearbox's first game, Half life: Opposing Force. One of the main enemies was called a Shock Trooper used a weapon that specializes in dealing shock damage.