This ultrasonic generator produces loud, siren-like, pulsating, and aggressive ultrasonic sounds that are perceived as extremely unpleasant by many animals and are therefore largely avoided. The generator should be used to keep rodents, insects, crawling parasites, wildlife, and birds at bay. The frequency of the sound can be adjusted between ultrasonic (inaudible to humans) and loud, high-pitched tones that are audible to humans.