Potions of Perception temporarily raise the chance of successful thieving rolls by 20%. This will last for 6 hours in-game time, which is more than 30 minutes real time. It's sold at Sorcerous Sundries and other stores and it may be found in containers across the Sword Coast. This item appears in Baldur's Gate, Baldur's Gate: Enhanced Edition and Baldur's Gate II: Shadows of Amn.