Potion of Defense sets the armor class of the imbiber to 0. After that, bonuses from armor are added to the armor class score. It lasts 10 turns, which 10 minutes in real-life. This item appears in Baldur's Gate, Baldur's Gate: Enhanced Edition, Baldur's Gate II: Shadows of Amn and Baldur's Gate II: Enhanced Edition.
In Baldur's Gate, it can be bought from Sorcerous Sundries.
|“||This potion is similar to the potion of invulnerability in that it improves the armor class of the imbiber. The effect lasts for 10 turns.||”|