If the holder has full HP and is hit by an attack that would otherwise cause fainting (including a one-hit knockout move), it survives with 1 HP. Can also protect against self-inflicted confusion damage. Protects from all strikes of a multi-strike move. Cannot protect from damage from Future Sight or Doom Desire. Disappears after use.
Generation V onward
From Generation V on, it can only protect from one strike of a multi-strike move.