Perks are passive perks and include bonuses like running faster, increased bullet damage, and also extra Equipment or Lethal Equipment.
Perk Tier 1
C4 x2
Remote detonation explosive.
Unlocked: Default
Special Grenades x3
3 special grenades. No smoke.
Unlocked: Default
RPG-7 x2
Rocket Launcher with 2 rockets.
Unlocked: Default
Claymore x2
Trip activated explosives mine.
Unlocked: Level 23
Frag x3
3 Frag grenades.
Unlocked: Level 41
Bandolier
Extra ammunition magazines.
Unlocked: Level 32
Bomb Squad
Ability to seek out enemy explosives.
Unlocked: Level 14
Perk Tier 2
Stopping Power
Increased bullet damage.
Unlocked: Default
Juggernaut
Increased health.
Unlocked: Default
Sleight of Hand
Faster reloading.
Unlocked: Level 20
Double Tap
Increased rate of fire.
Unlocked: Level 29
Overkill
Carry two primary weapons, no pistol.
Unlocked: Level 38
UAV Jammer
Undetectable on enemy radar.
Unlocked: Level 11
Sonic Boom
Higher explosive weapon damage.
Unlocked: Default
Perk Tier 3
Extreme Conditioning
Spring for longer distances.
Unlocked: Default
Steady Aim
Increased hip-fire accuracy.
Unlocked: Default
Last Stand
Pull out your pistol before dying.
Unlocked: Level 8
Martyrdom
Drop a live Grenade when killed.
Unlocked: Level 17
Deep Impact
Deeper bullet penetration.
Unlocked: Default
Iron Lungs
Longer breath for steadier sniper shots.
Unlocked: Level 26
Dead Silence
Make less sound when you move.
Unlocked: Level 44
Eavesdrop
Hear voice chat of nearby enemies.
Unlocked: Level 35