The following is a list of perks that can be unlocked:
Tier 1 PERK - LOCATION Flak Jacket - Reduces explosive damage. Flak Jacket Pro - Deflect fire damage, and safely toss back grenades. Ghost - Undetectable by the Spy Plane and Blackbird. Ghost Pro - Undetectable by aircraft, IR scopes, Sentry Guns, and no red cross hair on your name when targeted. Hardline - Killstreaks require one less kill. Harline Pro - Change the contents of a Care Package. Lightweight - Move faster. Lightweight Pro - No fall damage. Scavenger - Get ammo from fallen enemies. Scavenger Pro - Start with extra magazines, and get grenades from fallen enemies.
Tier 2 PERK - LOCATION Hardened - Bullets penetrate better. Hardened Pro - Increased bullet damage to killstreaks and less aiming recoil when shot. Scout - Hold breath longer. Scout Pro - Switch weapons faster. Sleight Of Hand - Faster reloads. Sleight Of Hand Pro - ADS with all weapons, except sniper rifles. Steady Aim - Increased hip-fire accuracy. Steady Aim Pro - Faster ADS after sprinting. Warlord - Equip two attachments to your primary weapon. Warlord Pro - Start with one extra lethal and tactical grenade (except Willy Pete).
Tier 3 PERK - LOCATION Hacker - Ability to detect enemy equipment and explosives. Hacker Pro - Booby trap enemy Care Packages and turn enemy killstreaks and equipment friendly. Marathon - Longer sprint. Marathon Pro - Unlimited duration. Ninja - Silent movement. Ninja Pro - Make no noise, and hear all enemies louder. Second Chance - Ability to use your pistol before dying. Second Chance Pro - Survive longer, and get revived by teammates. Tactical Mask - Protects against Nova Gas.