A new feature for Halo 4 has been announced on Halo Waypoint.
Called Specializations, these classes will unlock at Level 50. The classes will feature nine levels of cosmetic upgrades, like new helmets or weapon skins, before giving a class-specific ability on the 10th level.
There are eight Specializations, two of which will be available on Nov. 6: Wetworks (with Promethean Vision) and Pioneer (with XP bonus).
The other six Specializations (Engineer, Tracker, Rogue, Stalker, Pathfinder and Operator) will be released after launch. However, all eight classes will be unlocked on day one in the Limited Edition of the game.