The MISB-class was a model of freighter used during the Mandalorian Wars and other conflicts of the era.
Large, slow and clumsy, the ship's most impressive feature was its (then) considerable cargo capacity. Unarmed and boasting only weak shields, it was entirely dependent on other ships for defense. This all kept the costs of purchase and operation down, making the freighter desirable to those on a budget.
In 3,950 BBY, the Dark Army purchased several ships of the class for their use. The ships were converted into gunships with the addition of several laser turrets, and pressed into offensive roles. In this regard, they proved to be spectacularly unsuccessful, prone to crashing and exploding ad inopportune moments.