Halo 4 Class "Specializations" Revealed

• Wetworks: Wetworks users get protection against the wall-penetrating Promethean Vision Armor Ability. You'll still show up on the HUD of a player using it, but you'll be a slightly more inconspicuous outline rather than a big red blur. Also, you'll get a bit of sound dampening when you sprint.
• Pioneer: A good standby if you're looking to rank up fast - this Spec generates extra XP for any action you take while you've got it equipped.
• Engineer: As an Engineer, you'll be alerted to incoming weapon drops a couple of seconds ahead of other players, increasing the odds that you'll get their first. If you're close enough, the HUD will point the way with a GPS arrow.
• Tracker: Damn near killed yourself reaching a drop, only to find that it's stuffed with underpowered guns? As a Tracker, you'll have one chance to re-roll the contents.
• Rogue: Players of SWAT in Halo: Reach should prioritise this one - its Stability perk reduces scope wobble while zoomed. I dread to think of what DMR diehards will achieve with the thing.
• Stalker: A class for those who hold grudges. The Nemesis armor mod generates an icon of the last person who killed you, and also tracks those who've attacked you.
• Pathfinder: Only the biggest guns will do? Sign up as a Pathfinder for reduced cooldown on vehicle weapons, and easier carrying of emplaced guns.
• Operator: The Wheelman mod grants your ride a little extra resistance against EMPS. It also lets makes vehicle health recharge a bit faster. Fortunately, this latter bonus can't be stacked.

(Source: CVG)