Ultrasonic sound wave mouse repeller Ultrasonic Sound: Fixed 22KHZ,Variable 22-55KHZ Ultrasonic mouse repeller Technology:Ultrasonic Effective Area:50 sq metersSwitch:Fixed 22KHZ,Variable ... by air is acceptable! Note: when you use the Ultrasonic Repeller, it is better to put it above the ... the speaker direct the window or ceiling, or the ultrasonic sound wave will waste in the air. When you just ...