Tinted gray, their design consisted of a central hub from which five arms extended in a star-like formation. The starships possessed weapon systems "substantially superior" to those of the USS Voyager, using quantum resonance torpedoes as their primary armament. Defensively, they employed a complex subspace defense field, which meant Voyager's weapon systems posed very little threat to the Pralor vessel. However, at optimal efficiency, Voyager's engines were more powerful than those aboard the Pralor vessel.
The ships were used in the war between the Pralor and the Cravic. However, when the war ended and the Pralor and Cravic attempted to terminate the units, the units killed both species. The units used the Pralor and Cravic starships to continue the war for at least another fifty years. (VOY: "Prototype")