Firefly: Jetwash - Rules of Play says:
The Firefly: The Game – Jetwash booster adds a new Series IV Firefly to Firefly: The Game. Named for the late Hoban Washburne and built on the newer Series IV Firefly chassis, the Jetwash befits its namesake: fast, with plenty of tricks up its sleeve.
This game booster contains everything players need to add a new ship to Firefly: The Game. The Jetwash set contains a new Firefly Series IV model (yellow-green); ship card; color-coordinated ship dice (yellow-green); a drive core card; new ship upgrades; a new Leader crew card; sheet of game tokens; a new Set Up Card; and a new Story Card.