A sash was an article of clothing. It was often used for ceremonial purposes on a military uniform in various militaries at various instances in galactic history. They sometimes carried various patches representing actions they undertook during their service in a military.
During the Galactic Civil War, the Rebel Alliance starfighter pilot Keyan Farlander possessed a sash on his Rebel uniform, of which he had at least 18 Battle Patches and 3 Flight Badges by the time of the Battle of Yavin. Boba Fett wore an honor sash from his days as a Journeyman Protector.