You have a bonus to Armor Class while wearing this armor. The bonus is determined by its rarity.
Rarity by bonus: +1 — uncommon; +2 — rare; +3 — very rare
Available as: Breastplate, Chain Mail, Chain Shirt, Half Plate Armor, Hide Armor, Leather Armor, Padded Armor, Plate Armor, Ring Mail, Scale Mail, Shield, Splint Armor, Studded Leather Armor.