ShadowDagger Bracer (3.5e Equipment)
From D&D Wiki
 ShadowDagger Bracer
Made of dark tanned leather, this bracer magically brings forth daggers of shadow. Each shadow dagger is a glossy black and has the weight, characteristics and appearance of a mundane dagger. As a free action and only when the hand wearing the bracer is empty may its wearer produce a dagger. The weapon appears in the wearer's grip. Separating more than 60 ft from the bracer or existing for more than one minute causes a dagger to dissipate. Only five daggers can exist at one time, the elder weapon vanishing if the wearer exceeds the limit. Unlike ordinary daggers, shadow daggers harm and can be wielded by incorporeal creatures as if they possessed the ghost touched ability.