The MW3 multiplayer perks give you a variety of different enhancements, but you can only choose 3 perks per class. Some perks are available initially, while others are unlocked as you rank up. There are a total of 15 perks and they are divided into 3 slots.
The Modern Warfare 3 pro perks system works the same way as it did in Modern Warfare 2 and Black Ops; you unlock the pro versions by doing their specific challenges.
Perk Slot 1
Every enemy that takes explosive damage is marked as a red arrow on the radar, which also shows the direction the enemy is facing.
Pro Ability: Same as above, but it's achieved by causing bullet damage to the enemy.
Reload your weapons 50% faster than normal. Sleight of Hand is extremely useful with Light Machine Guns since they have long reload times.
Pro Ability: Pick up and swap weapons 50% faster than normal.
Enemy air support and sentries can't detect you.
Pro Ability: Faster launcher lock-on + extra bullet damage vs. enemy air support. This makes Light Machine Guns extremely effective against enemy air support.
Allows you to sprint 2x times longer. Press and hold the left analog stick on the Xbox 360 (LS) or PlayStation 3 (L3) to sprint.
Extreme Conditioning is useful for aggressive rush tactics.
Pro Ability: Climb obstacles faster.
Replenishes your ammunition when you walk over Scavenger bags that are dropped by players when they die. Grenade launcher ammo can only be replenished if the player that dropped the Scavenger bag had the same ammo.
Pro Ability: Extra starting magazines.
Perk Slot 2
Allows you to aim down the sight 50% faster than normal. Quickdraw is ideal for quick-scoping with Sniper Rifles.
Pro Ability: Allows you to recover from equipment and grenade usage faster.
Greatly reduces explosive damage.
Pro Ability: Makes you immune to Stun and Flash Grenades.
Reduces the amount of kills required for any killstreak by one. For example, the Care Package normally requires 4 kills, but with Hardline, you only need 3 kills. This perk returns in BO2, but will instead give you more points per action; check out the black ops 2 perks for other familiar MW3 counterparts.
Pro Ability: Two kill assists add one kill towards your next killstreak. Deathstreaks require one less death.
Makes you undetectable by UAV, thermal scopes, Heartbeat Sensors and Portable Radars. You can still show up on the radar if you fire a weapon that doesn't have a silencer.
Assassin doesn't protect you from the Recon perk or the Recon Drone killstreak.
Pro Ability: Makes you immune to Counter-UAV and EMP. Enemies won't see a red crosshair or name when targeting you.
Allows you to carry two primary weapons, but the second primary weapon can't be equipped with attachments.
Pro Ability: Your second primary weapon can now be equipped with attachments.
Perk Slot 3
Allows you to identify enemies from farther away by showing their names at a greater distance.
Pro Ability: Allows you to hold your breath 2x times longer than normal when steadying a weapons scope.
Faster movement while aiming down the sight.
Pro Ability: Delays enemy detection-triggered explosives, like Claymores and Bouncing Betties.
Highlights enemy explosives and tactical equipment in red.
Pro Ability: Makes enemy footsteps louder and also cancels out Dead Silence.
Increases hip-fire accuracy.
Pro Ability: Allows you to aim down the sight faster after sprinting.
Makes you silent and also reduces the effect of the Recon perk.
Pro Ability: You don't take any damage from falling.
COD: Modern Warfare 3
Xbox 360, PlayStation 3 and PC. Multiplayer is available on Xbox LIVE (Xbox 360), PSN (PS3) and Steam. Xbox LIVE requires Gold Membership.
Call of Duty: Black Ops 2
The next Call of Duty game comes out on November 13th, 2012 for the current generation consoles and PC. Black Ops 2 takes place in 2025, which means multiplayer will feature futuristic weaponry and maps. Perks in BO2 have been balanced and Killstreaks replaced with Scorestreaks.