Armor is a type of character equipment.
Every character wears head, arms, chest and leg armor and a class item. Each piece of armor can be worn only by a character of a certain class.
Armor pieces can be Common, Uncommon, Rare, Legendary or Exotic. As of New Light, the player can obtain only Rare or better armor, although Common and Uncommon are unlocked in their collection and can be reclaimed from it. Exotic armor has special perks, but a character can wear only one piece of Exotic armor at a time.
Each armor piece has a certain element, a Power level and provides stats like mobility, resilience, recovery, discipline, strength and intellect. The average power of a character's equipped gear is that character's power level, which determines how much damage they take from enemies and deal to them. Stats decrease ability cooldowns and provide additional benefits to characters. The armor's elemental affinity determines which mods can be installed into it.
Mods are special items that can be installed into a character's gear to provide them additional benefits. The player can slot mods into every piece of armor that is Rare or better.
Each armor piece has sockets for specific types of mods. General Armor Mod sockets can be found on every piece of armor, while Helmet Armor Mods, Arms Armor Mods, Chest Armor Mods, Leg Armor Mods and Class Item Mods can be installed only into armor of the specified type. Combat Style Mod sockets can accept Charged with Light and Warmind Cell mods and Raid armor has sockets for mods from that raid.
Every armor piece has a certain elemental affinity and a charge value. The charge can be increased by upgrading that piece of armor, and the element can be changed by consuming an Upgrade Module, and the total upgrade materials necessary to reach the armor's charge level if the player wants to keep it upgraded. Installing a mod takes a certain amount of charges, which it occupies until the mod is removed or replaced with another. Some mods have an elemental cost and can be installed only into armor of a corresponding elemental type.
For example, Ashes to Assets is a Helmet Armor Mod with a cost of 3 Solar charges. It can be installed only into the Helmet Armor Mod socket on a head armor piece with a Solar affinity that has at least 3 free charges.