There are many rumors about the Black Ops Level System, but there is only one fact in every lie. You Prestige when reaching level 50 is it? To prestige. There are a total of 14 Prestiges you can go up to.
The following are the perks:
Perk Slot 1
Lightweight | Lightweight Pro
Ability: This allows you to move faster, but how fast depends on the weapons mobility.
Pro Ability: This gives you the chance to aim faster after sprinting.
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Scavenger | Scavenger Pro
Ability: Resupply from dead players. This is great for weapons and launchers that run out of ammo quickly.
Pro Ability: Doubles your ammo with extra magazines.
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Ghost | Ghost Pro
Ability: Ghost is similar to the Cold Blooded perk from Modern Warfare 2. Enemy AI controlled killstreak rewards are unable to see or attack you. You only show up on the radar if you fire a weapon that doesn't have a silencer.
Pro Ability: The enemy won't see your name or a red crosshair when targeting you.
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Flak Jacket | Flak Jacket Pro
Ability: This perk reduces explosive damage and allows you to survive nearly any indirect explosive attack. The Flak Jacket was first featured in Call of Duty: World at War.
Pro Ability???
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Hardline | Hardline Pro
Ability: Killstreaks require 1 less kill. For example, the RC-XD normally requires 3 kills, but with Hardline you only need 2 kills.
Pro Ability: ???
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Perk Slot 2
Hardened | Hardened Pro
Ability: This gives your weapon increased bullet penetration. Works just like the FMJ attachment from Modern Warfare 2.
Pro Ability: ???
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Scout | Scout Pro
Ability: Increases the time you can steady a weapons scope. This is very useful with sniper rifles.
Pro Ability: ???
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Steady Aim | Steady Aim Pro
Ability: Significantly increases hip fire accuracy. This should be used with the Dual Wield attachment, since Dual Wield prevents you from aiming down on the sights.
Pro Ability: ???
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Sleight of Hand | Sleight of Hand Pro
Ability: Cuts the weapons reload time in half. This should be familiar to Call of Duty veterans. Useful with light machine guns since they have long reload times.
Pro Ability: Allows you to aim faster. This halves the time it takes to aim down the sight
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Warlord | Warlord Pro
Ability: Bling returns from Modern Warfare 2 with a new name. This allows you to equip 2 attachments to your primary weapon.
Pro Ability: Allows you to equip 2 attachments to your primary and secondary weapon.
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Perk Slot 3
Marathon | Marathon Pro
Ability: Extends your sprint time. Marathon does not increase sprint speed or give you unlimited sprint.
Pro Ability: ???
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Ninja | Ninja Pro
Ability: Makes your footsteps silent, thus giving you a powerful stealth advantage.
Pro Ability: ???
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Second Chance | Second Chance Pro
Ability: Allows you to survive a normal death. You will drop to the ground and pull out your handgun. Second Chance ends after 10 seconds or if you take a single hit from the enemy, and in both cases, you will die.
Pro Ability: You can use your equipment as well as your handgun.
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Hacker | Hacker Pro
Ability: This works like SitRep from Modern Warfare 2. Hacker allows you to detect enemy explosives and equipment like Tactical Insertions, Camera Spikes, Jammers, etc.
This highlights them with a red color.
Pro Ability: Allows you to booby trap enemy Care Packages and turn enemy killstreaks and equipment friendly. For example Sentry Guns, Claymores, SAM Turrets, etc.
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Tactical Mask | Tactical Mask Pro
Ability: Significantly reduces the effects of flashbangs and concussion grenades.
Pro Ability: ???
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Subject: Player Customization 
