Successfully complete the indicated task to unlock the corresponding perk:

Perk Slot 1

Special Grenade x3: Reach Level 4 (three special grenades, no smoke).
Satchel Charge x2: Reach Level 4 (two remote detonation explosives).
M9A1 Bazooka x2: Reach Level 4 (bazooka with two rockets).
Bomb Squad: Reach Level 16.
Bouncing Betty x2: Reach Level 24.
Bandolier: Reach Level 40.
Primary Grenade x2: Reach Level 44.
M2 Flamethrower: Reach Level 65.

Perk Slot 2

Stopping Power: Reach Level 4 (increased bullet damage).
Fireworks: Reach Level 4 (higher explosive weapon damage).
Flak Jacket: Reach Level 4 (reduce explosive damage).
Gas Mask: Reach Level 4 (protect against Tabun Gas).
Juggernaut: Reach Level 4 (increased health).
Camouflage: Reach Level 12.
Sleight Of Hand: Reach Level 28.
Shades: Reach Level 32.
Double Tap: Reach Level 36.
Overkill: Reach Level 56.

Perk Slot 3

Deep Impact: Reach Level 4 (deeper bullet penetration).
Extreme Conditioning: Reach Level 4 (sprint for longer distances).
Steady Aim: Reach Level 4 (increased hip fire accuracy).
Toss back: Reach Level 6 (reset fuse of picked up grenades).
Second Chance: Reach Level 9 (revive downed allies).
Martyrdom: Reach Level 20.
Fireproof: Reach Level 48.
Dead Silence: Reach Level 52.
Iron Lungs: Reach Level 60.
Reconnaissance: Reach Level 64.

Vehicle Perks

Water Cooler: Reach Level 4 (decreased turret overheat).
Greased Bearings: Reach Level 4 (increased turret rotation speed).
Ordnance Training: Reach Level 12.
Lead Foot: Reach Level 28.
Coaxial Machine Gun: Reach Level 40.