Halo 4 Armor Unlocks Guide: Armor Sets, Visors, Stances

Specializations

Specializations become available to you once you reach the max level (50), at which point you can select a specialization to level up to 10. As you gain levels in a specialization, you will earn a variety of unlocks. Each specialization contains an armor set, a skin, a weapon skin, a custom visor color, and a specialization ability. Once you max out a specialization, you can choose another specialization to level up in.

Wetwork : Specialization
Pioneer : Specialization
Engineer : Specialization
Tracker : Specialization
Rogue : Specialization
Stalker : Specialization
Pathfinder : Specialization
Operator : Specialization