Obscurity affects the visibility of a creature or object to other creatures in an area. A creature is considered to be Obscured while located in a Lightly Obscured or Heavily Obscured area, and will gain the conditions Lightly Obscured or Heavily Obscured respectively. Otherwise, they are considered to be in a Clear Area.
A wide variety of Equipment can bestow specific benefits on the player when they are in an Obscured state. Unless specified otherwise, a creature does not need to be Hiding to gain these bonuses, as long as the area they are standing in is Lightly or Heavily Obscured. If an item states that the user or target must be obscured without specifying Lightly Obscured or Heavily Obscured, both types of obscurement will fulfill this requirement.
Items which grant special benefits when obscured
Weapons
Clothes and Armour
Headwear
Rings