Uskura

Worn by most adult deep Imaskar, these magic items contain a more powerful version of the unseen servant spell. Nearly any object can be an uskura, although amulets and ioun stones are favored. A typical uskura produces an effect identical to that of an unseen servant spell. (caster level 10th), except that it has an effective Strength score of 6 and moves at a speed of 30 feet. An uskura may be activated for a total of 100 minutes per day, although this duration need not be consecutive. Many Imaskari either have multiple uskuras or create them at higher caster levels to provide them with around-the-clock service.
Moderate conjuration; CL 10th; Craft Wondrous Item, unseen servant; Price 36,000 gp. -
Source: Underdark