Designed by Sienar Fleet Systems, the Sigma-class long-range shuttle was equipped with a Class 1.0 hyperdrive and a Class 8.0 backup, along with a navicomputer. It was also outfitted with double heavy laser cannons and could carry ten passengers in addition to a minimum crew of one. The shuttle was able to hold three months' worth of consumables, and it supported up to 200 tons of cargo.
A variant of the Sigma-class was utilized by Emperor Roan Fel's personal bodyguards, the Imperial Knights. Such craft were able to carry a maximum of three Predator-class starfighters but only thirty tons of cargo as a result of the decrease in available space. Painted in crimson, reminiscent of the color of the Knights' armor, the variant bore the Imperial crest on its ventral surface and upper wing.
The Sigma-class was often employed to transport high-ranking Imperial officers and other diplomats throughout the galaxy. Whereas the Nune-class Imperial shuttle was limited to interplanetary travel in a given sector of space and commonly used as a troop transport, the Sigma-class was quite the opposite. Though not as extravagant as a luxury yacht, it was considered a luxury transport that provided comfort during long galactic travels. The interior of the shuttle consisted of a well-stocked kitchen, several large passenger compartments, and an open cargo space large enough to store personal speeders.