It's most noticeable feature were three cloaking devices placed in different sections of the ship. However, the only known ship of it's class, the Xerxes, was destroyed during the Fondor shipyard assault, after sabotage by Death Watch Mandalorians in service of the Confederacy of Independent Systems. When that occurred, Palpatine expressed his anger at Count Dooku for allowing it to happen, and executed the ship's commander, who survived the destruction of the Xerxes, Captain Yarus.