Leather Armor +3

Leather Armor +3 is a heavy enchanted piece of body armor, it is the strongest non-studded armor and the lightest body armor in the game of Baldur's Gate, but Studded Leather Armor +2 and Shadow Armor provide better protection to characters which can only wear leather armor as body armor. Compared to Leather Armor, this has armor class of 5, which is three points better and has weight of 4 lbs, making it 11 points lighter in weight. This piece of armor is found in Durlag's Tower at the last level before the demonknight. In which area it can be found on that lelvel is not known.

In-game description
"Leather armor +3:Karajah was Calishan's undisputed champion of pit fighting for a decade. Wearing only a thin leather armor and spiked gauntlets, he would pummel his foes to the ground, seemingly impervious to their blows. Eventually it was revealed that his armor was heavily enchanted at which point angry spectators threw him into the pit with a club-wielding ogre. The beast managed to break all of Karajah's bones while the armor remained as good as new."