Sundering Gauntlet (3.5e Equipment)
From D&D Wiki
Sundering Gauntlet: A warrior armed with a sundering gauntlet is far more dangerous than she first appears. The sundering gauntlet itself provides a +1 shield bonus to armor class (although a sundering gauntlet cannot be used with a shield). The warrior can choose to forgo this bonus, however, and treat the sundering gauntlet as a light weapon for the purposes of two–weapon fighting. When used in this manner, the sundering gauntlet can only be used to make sundering attacks on an opponent's weapon. A sundering gauntlet cannot be used to make sundering attacks on shields or armor, although an item held in the hands (such as a rod or wand) could be attacked by a sundering gauntlet. The wielder may decide, at the beginning of her initiative each round, whether to use the sundering gauntlet defensively, or to attack with it (and thus lose the shield bonus to her armor class).
Sundering attacks made with a sundering gauntlet do not draw an attack of opportunity. A sundering gauntlet can be used to make an attack of opportunity, but only if the wielder has chosen to use the sundering gauntlet offensively (and so has foregone the shield bonus). A warrior can choose to forgo any attack with another held weapon, and attack with a sundering gauntlet as her weapon, avoiding the combat penalties for fighting with two weapons. If the sundering gauntlet is worn on the off-hand, only half of the user's strength bonus is applied to damage, like any other off-hand weapon..