Perks

Perks are Call of Duty 4: Modern Warfare 's, Call of Duty: World at War 's, and Call of Duty: Modern Warfare 2 's multiplayer modifiers that passively affect game play, allowing further customization of classes. They affect available equipment, effectiveness of the player's equipment, the usefulness of the enemy's equipment, and the physical properties of the player's character.

List of perks in Call of Duty 4: Modern Warfare
Some perks are available initially while others are unlocked as the player progresses through multiplayer ranks. Up to three perks, one of each tier, can be equipped at one time. The tiers are colour coded blue, red, and green and therefore only one of each can be equipped.

First Tier
These perks deal with a player's equipment and/or explosives.

Bomb Squad
 * Warns players of enemy explosives. (Unlocked at level 14)

C4 x2
 * Two blocks of Composition-4. (Available at level 1)

Claymore x2
 * Two Claymore mines. (Unlocked at level 23)

RPG-7 x2
 * Two RPG-7s. (Available at level 1)

Special Grenades x3
 * Three Flash Grenades or three Stun Grenades (Available at level 1)

Bandolier
 * Extra ammunition. (Unlocked at level 32)

Frag x3
 * Three Fragmentation Grenades. (Unlocked at level 41)

The following attachments replace Perk 1:

M203 Grenade Launcher/ GP-25 Grenade Launcher
 * Attaches a high-velocity impact grenade launcher to an assault rifle.

Foregrip
 * Decreases the recoil of light machine guns and shotguns.

Second Tier
Juggernaut
 * Increases health by 25% (is canceled out by the "Stopping Power" perk)

Sleight of Hand
 * Faster reload. (Unlocked at level 20)

Sonic Boom
 * Increased explosive damage by 40%

Stopping Power
 * Increases bullet damage by 25% (is canceled out by the "Juggernaut" perk)

Double Tap
 * Decreases time between bullets by a third. (Unlocked at level 29)

UAV Jammer
 * Makes the player unseen to enemy UAVs. (Unlocked at level 11)

Overkill
 * Carry two primary weapons. (Unlocked at level 38)

Third Tier
Deep Impact
 * Increased bullet penetration.

Extreme Conditioning
 * Sprint for longer distances.

Last Stand
 * Pull out your pistol before dying. (Unlocked at level 8)

Martyrdom
 * Drop a live grenade when killed. (Unlocked at level 17)

Steady Aim
 * Increases hip-fire accuracy.

Dead Silence
 * Reduces the footstep noise. (Unlocked at level 44)

Iron Lungs
 * More steadying time for sniping. (Unlocked at level 26)

Eavesdrop
 * Hear enemy voice chat. (Unlocked at level 35)

First Tier
Special Grenades x3
 * Gives the player 3 special grenades excluding smoke grenades.

Satchel Charge x2


 * Similar to the C4 x2 in Call of Duty 4.

M9A1 Bazooka x2
 * Similar to the RPG x2 in Call of Duty 4, perhaps more accurate.

Bomb Squad
 * Same as it was in Call of Duty 4, you can see where enemy Satchels and Bouncing Betties are located.

Bouncing Betty x2
 * Similar to the Claymore x2 in Call of Duty 4, mines that are planted in the ground.

Bandolier
 * Increases initial ammo for your selected weapons.

Primary Grenades x2
 * 2 frag grenades, sticky grenades, or Molotov Cocktails.

M2 Flamethrower
 * The player is equipped with a flamethrower.

The following attachments replace Perk 1:

Rifle Grenade Foregrip
 * Attaches a high-velocity impact grenade launcher to a semi-automatic or bolt-action rifle.
 * Decreases the recoil of shotguns.

Second Tier
Stopping Power
 * Each bullet does 25% more damage and is canceled out by the "Juggernaut" perk.

Fireworks
 * Explosive damage is increased by 40%.

Flak Jacket
 * Explosive damage dealt to the player is decreased.

Gas Mask
 * The effects of Tabun gas are decreased.

Juggernaut
 * Health is increased by 25% and is canceled out by the "Stopping Power" perk.

Camouflage
 * The player doesn't get exposed by recon planes. Identical to UAV Jammer.

Sleight of Hand
 * Reloading is quicker.

Shades
 * Reduces the effect of signal flares on the player's vision. Not available on the Wii version.

Double Tap
 * Decreases time between bullets by a third.

Overkill
 * Allows the player to wield 2 primary weapons (meaning no pistols). Same as Call of Duty 4.

Third Tier
Deep Impact
 * Gives the user's weapon more penetration power.

Extreme Conditioning
 * Gives the player the ability to sprint longer.

Steady Aim
 * More accuracy when firing from the hip. Note: this does not help with aiming down the sights.

Toss Back
 * When tossing back a grenade, it resets the grenade fuse.

Second Chance
 * Almost the same thing as Last Stand in Call of Duty 4 except you survive much longer and another player who has Second Chance will be able to revive them.

Martyrdom
 * When the player is killed, they drop a live grenade.

Fireproof
 * Damage from fire done to the player is reduced.

Dead Silence
 * The player barely makes noise when walking or sprinting.

Iron Lungs Reconnaissance
 * Gives the user the ability to hold their breath with a sniper rifle for 10 seconds instead of 4. Not avalable on the wii verson
 * Gives the player the ability to see all artillery, dogs, and tanks on the map.

Vehicle Perks
Water Cooler
 * Decreased turret overheating.

Greased Bearings
 * Increased turret rotation speed.

Leadfoot
 * Increases the speed of the tank.

Ordnance Training
 * Boosts the firing rate of the tank's main firing cannon.

Coaxial Machine Gun
 * Allows the driver to use a coaxial machine gun only in the front of the tank.

Please note that Shades, Reconnaissance, Iron Lungs and Vehicle perks are not available on the Wii version of Call of Duty: World at War

List of Perks in Modern Warfare 2
Along with standard perks, players will now be able to unlock improved "Pro" versions of certain perks by fulfilling certain requirements while using them. These "Pro" versions include the original abilities of the perk, but also add new benefits. Many of the perks that were in Call of Duty 4 or 5 that are missing are now either part of a Pro perk, or available as weapon attachments, such as Deep Impact (FMJ), and Double Tap (Rapid Fire). The Overkill perk has been replaced partially by the inclusion of Machine Pistols, Shotguns, and Launchers as secondary weapons. Interestingly, if a Perk Challenge IV is achieved mid-game the "Pro" version will take effect immediately for all classes equipped with that perk.



Second Tier
This Tier deals with the effects on Damage (Stopping Power/Danger Close), Movement (Lightweight) and bonus effects on Killstreaks (Hardline/Cold-Blooded).

Stopping Power(Unlocked at level 1)
 * Increased bullet damage by 25%.
 * Stopping Power Pro: Increased damage versus vehicles.

Lightweight(Unlocked at level 1)
 * Move 7% faster.
 * Lightweight Pro: Quick aim after sprinting.

Hardline(Unlocked at level 9)
 * Killstreaks require 1 less kill.
 * Hardline Pro: Deathstreaks require 1 less death.

Cold-Blooded(Unlocked at level 25)
 * Makes the user invisible to enemy thermal optics, and enemy killstreaks. Possesses the powers of UAV Jammer and Camouflage.
 * Cold-blooded Pro: No red crosshair or name when targeted.

Danger Close(Unlocked at level 33)
 * Increased explosive damage. (replaces Sonic Boom and Fireworks)
 * Danger Close Pro: Increased damage from killstreak rewards.

Third Tier
This tier effects the enemy players equipment (Scrambler/Ninja/Sitrep)and gives players a tactical advantage in combat (Steady Aim/Commando/Last Stand).

Commando(Unlocked at level 1)
 * Increased melee lunge distance.
 * Commando Pro: No falling damage.

Steady Aim(Unlocked at level 1)
 * Increased hip-fire accuracy.
 * Steady Aim Pro: Breath can be held longer during sniping. (Replaces Iron Lungs)

Scrambler(Unlocked at level 17)
 * Jams the enemy radar when they are close enough.
 * Scrambler Pro: Delays enemy claymore explosions.

Ninja(Unlocked at level 29)
 * Makes Player invisible to the Heartbeat Sensor.
 * Ninja Pro: 4x quieter footsteps. (Replaces Dead Silence)

SitRep(Unlocked at level 37)
 * Detect enemy explosives (Claymores and C4) and Tactical Insertions. (Replaces Bomb Squad)
 * SitRep Pro: 4x louder enemy footsteps (Does not affect Ninja Pro users, whose footsteps remain at 1/4x regular volume).

Last Stand(Unlocked at level 41)


 * Use a pistol while bleeding out prior to death.
 * Last Stand Pro: Use your equipment in Last Stand.

Trivia

 * There were rumours on the internet of a "monkey man" perk on Call of Duty: World at War, allowing the ability to climb trees, although there has never been any evidence of the perk.
 * The monkey man perk was even more convincing after a glitch on Makin was found, allowing the player to jump on top of a tree.