Used Power-on confirmed Opened for inspection Please refrain from purchasing if you are sensitive to used items. Please refer to the manufacturer's website for details. Automatically emits ultrasonic waves in response to a dog's barking See details for installation in places where you want quiet, such as the entrance or living room When a dog barks, it automatically emits ultrasonic waves that dogs dislike. Maximum range is 15 meters. Gentle training with harmless ultrasonic waves When the doorbell rings or when guests arrive, it automatically emits ultrasonic waves in response to a dog's barking. Since it is ultrasonic waves that humans cannot hear, it is quiet and does not harm dogs. The average human hearing frequency is 20Hz to 20KHz, and dogs can hear a wide range of 15Hz to 120KHz. This product emits ultrasonic waves of ~25KHz, which dogs can hear but humans cannot. Of course, it will not hurt your dog with vibrations or electric shocks. Can be placed or hung *For indoor use only, so it cannot be installed outdoors It is water-resistant, but submerging it in water or leaving it in the rain outdoors may cause malfunction, so please be careful about the installation location.