Mice and rats, which live in this country and unwantedly roam our households, have a very acute sense of hearing. Compared to humans, these rodents perceive much higher frequencies. Mice and rats communicate with each other in the ultrasonic range, with only sounds of fear or anger being partially audible to humans. This device takes advantage of this characteristic by emitting sound waves in the ultrasonic range that are inaudible to humans but can become uncomfortable for mice and rats over time. This ensures that the animals look for a quieter spot.