Shuttle S257 was a Sentinel-class landing craft of the Galactic Empire's naval forces. Sometime in 4 BBY, the shuttle was stolen by the rebels of Phoenix Cell, where it was used by Kanan Jarrus and Rex in their mission to an experimental Interdictor-class Star Destroyer in order to rescue Jarrus' Padawan, Ezra Bridger, and Commander Jun Sato.
A Sentinel-class landing craft, Shuttle S257 was equipped with a hyperdrive generator and communications system which was compatible with the communications of an Interdictor-class Star Destroyer. The shuttle also came armed with its own weapon systems near its forward ramp and along its articulated wings.
- Star Wars Encyclopedia of Starfighters and Other Vehicles