Description Ultrasonic Bark Control: When your dog (or your neighbor's dog) starts barking, this device emits a safe but annoying high-pitched ultrasonic sound; when the barking stops, the tone also stops in any season and in all weathers Conditions Use this bark stopper to stop excessive barking We help pets and their people live happily together The ultrasonic bark stopper is placed within range of the barking dog, the internal microphone picks up the sound and the device automatically starts. Ultrasound waves can be heard by dogs but are silent to humans. Outdoor silencers can be hung on trees, indoors, on outdoor walls or fence posts to stop dogs from barking. Make sure the ultrasonic bark house is facing the dog and within 50 feet of the dog. Ultrasonic bark controller uses high-frequency sound to reduce excessive barking of dogs within hearing range; suitable for dogs 3 months and older, with a range of up to 50 feet. 3 sensitivity adjustment levels (15-30KHZ) Long standby time (2 months) Product size: 10.3CM*4.5CM*6.2CM Note: If the dog is deaf or hearing impaired, he may not respond to the barking control device reaction. Packing list: 1 piece ultrasonic bark plug