The dog barking control device automatically emits dog-sensitive ultrasonic waves. Once the dog stops barking, the bark control device will automatically stop emitting ultrasonic waves. The sensitive microphone automatically detects barking dogs up to 50 feet away (works for neighbor's dogs too). Durable and waterproof design, so you can install it outdoors, at home, and more using the included mounting hardware. Four adjustable levels of sensitivity and frequency, so you can adjust to any level you want. Different dogs may be sensitive to different frequency bands of ultrasound. Please test different frequency bands for best results. Level 1, Frequency: 15 KHz, Sensitivity: Low, Effective Range: 15 ftLevel 2, Frequency: 20 KHz, Sensitivity: Low, Effective Range: 30 ftLevel 3, Frequency: 30 KHz , Sensitivity: Medium, Effective range: 50 feetLevel 4, Frequency: 15-30 KHz, Sensitivity: High, Effective range: 15-50 feetUsing ultrasonic barking control device can effectively prevent you or your neighbors from barking The dog barks. This device can help create a more peaceful environment. Ultrasonic dog barking deterrent uses high-pitched ultrasonic technology. The sound of ultrasonic waves is above the human hearing range, but it will attract the attention of dogs. Safe for humans and dogs. USB powered, no batteries requiredThe device only takes 3 hours to charge and can work continuously for 30 days after being fully charged. Dog deterrent device is not suitable for use in the following situations: aggressive dogs, noisy environments, hearing-impaired dogs, dogs under 6 months or over 8 years old, or noisy environments caused by music, etc.Package list :1X Bark Stopper1X Charging Cable1X Screw Bag1X Instruction Manual