The following perks have the corresponding effects:
PERK - EFFECT Marathon - Unlimited sprint. Sleight of Hand - Faster reloads. Scavenger - Resupply from dead enemies. One Man Army - Change classes at anytime at the loss of a secondary weapon. Stopping Power - Increase bullet damage against enemy players. Lightweight - Move quicker. Hardline - Killstreaks require one less kill. Cold Blooded - Undetectable by UAVs, air support, sentry guns and thermal vision. Danger Close - Increased explosive weapon damage. Commando - Increased melee distance. Steady Aim - Increased hip-fire accuracy. Scrambler - Jams enemy radar near you. Ninja - Invisible to heartbeat sensors. SitRep - Detect enemy explosives and tactical insertions. Last Stand - Fall to the ground and use your secondary weapon until you bleed out. Bling - Two primary weapon attachments.