Shield Wall

From WoWWiki

Shield Wall
Shield Wall Instant Reduces the damage taken from melee attacks, ranged attacks and spells by 60% for 10 sec.
Usable by
Class	Warrior
Properties
Type	Defensive
School	Physical
Cooldown	5 minutes
Talents
Improvement talents	Improved Disciplines
Other information
Requirements	Shields, Defensive Stance
Related buff
Shield Wall Damage reduced by 60%. Duration: 10 seconds

"Sometimes the best offense is a sound defense, and it can pay to just dig in and hope for the best. With all thoughts bent on simply staying alive, the Warrior hunkers down and puts that shield to good use."

Shield Wall is a defensive self-buff that costs no Rage. It has a 5 minute cooldown. As of patch 3.0.2, it is NO longer linked to the Retaliation or the Recklessness timers. When activated it absorbs 60% of all incoming damage, for 10 seconds. It is learned at level 28 for 1 10 .

Available in Defensive Stance only, and requires an equipped Shield.

Notes

As of patch 3.0.2 Shield Wall is no longer linked to Recklessness or Retaliation, making all three of these talents usable in PvP. Shield Wall falls into Panic button territory, and is best saved for when you just have to survive a little bit longer. Examples include an OOM healer, just a few adds too many, an enraged end-instance/Raid Boss, too many stacks of a debuff that reduces healing received, or a Battle Ground flag run.

Shield wall is the most powerful form of damage reduction in the game, and is extremely effective at keeping the warrior alive. In addition, shield wall does not drop aggro, so it allows a warrior to continue tanking, unlike Blessing of Protection.

For more day-to-day panic, there may be less extreme measures available; Hamstringing or Piercing Howl before running, potions, using the much faster cooldown Shield Block while you finish it off, or even just dying and being raised again by the group healer if it doesn't look like a total wipe is hinged on your survival. Bear in mind that it isn't an invulnerability shield, and even 40% damage from a ?? Elite can still hurt plenty.