A shrieker, the common name for a sonic emitter, functioned by generating a piercing, high-pitched noise. This noise served the purpose of briefly incapacitating hostile persons. An example of this technology was found in Lightning, the astromech droid belonging to Florn, a bartender at the Zero Angle. He deployed it at least once to quell a brawl that had erupted between Imperial Navy pilots and Imperial Army pilots.