The following perks are available.

Enforcer

Level 1
Fast Throw: Keeps your grenade accessible.
Reduced Fall: Allows you to survive falling longer distances.

Level 2
Fast Ready: Bring your weapons to bear faster after sprinting.
Upgraded Ammo Box: Carry two ammo boxes into battle.

Level 3
Fast Aim: Bring your weapon to bear faster when aiming down sights.
Extra Charges: Carry and deploy more breaching charges at once.

Level 4
Increased Suppression: Increases the effect of suppression on opponents.
Reduced Suppression: Reduces the effects of suppression on you.

Professional

Level 1
Fast Climb: Climb ropes, ladders, and walls faster.
Reduced Fall: Survive falling longer distances.

Level 2
Advanced Spot: Targets remain spotted for a longer duration.
Fast Unspot: Reduces the time you stay spotted by opponents.

Level 3
Hold Breath: Hold your breath for longer, giving you a longer window of time to steady your scope.
Low Profile: Undetected by cameras and security cameras, except when sprinting.

Level 4
Fast Reload: Reload your weapons much faster.
Delayed Trigger: Laser tripmines and Sabotage have an extra delay before triggering, giving you a chance to avoid them.

Mechanic

Level 1
Extra Grenade: You can carry an additional grenade.
Flak Jacket: Reduces explosive damage, allowing the wearer to survive an otherwise lethal blast.

Level 2
Extra 40mm Grenades: Increases the amount of carried 40mm grenade launcher ammunition.
Fast Repair: Increases the effectiveness of the Repair Tool.

Level 3
Fast Aim: You can bring your weapon to bear faster when aiming down sights.
Delayed Trigger: Tripmines and Sabotage have an extra delay before triggering, giving you a chance to avoid them.

Level 4
Fast Reload: Practice makes perfect—you can reload your weapons much faster.
Fast Swap: Rapidly swap between weapons and gadgets.