INFORMATION ABOUT THIS PRODUCT Made of high quality material, durable and robust, wear and corrosion resistant. 4 different adjustable sensitivity and different frequencies, easy do adjust, with effective range of 15-50 feet to meet your needs. Rechargeable via USB, charging only takes 3 hours and can be used for about 30 days. Safe and harmless, thanks to ultrasonic technology, it can effectively prevent dogs from barking, creating a peaceful environment. Waterproof, not afraid of difficult conditions, suitable do both indoor and outdoor use. Four adjustable sensitivity and frequency levels, so you can set any level. Different dogs may be sensitive to different ultrasound frequency bands. For best results, you need to test different frequency bands. Level 1, Frequency: 15 KHz, Sensitivity: Low, Effective Range: 15 feet Level 2, Frequency: 20 KHz, Sensitivity: Low, Effective Range: 30 feet Level 3, Frequency: 30 KHz, Sensitivity: Medium, Effective Range: 50 feet Level 4, Frequency: 15-30 KHz, Sensitivity: High, Effective Range: 15-50 feet Dog repellents are not intended do use in the following situations: aggressive dogs, noisy environment, hearing impaired dogs, dogs under 6 months of age or over 8 years of age, noisy environment caused by music. Specifications: Color: As shown Material: Plastic Sensitivity: 4 levels Frequency: 15-30 kHz Effective Range: 15-50 feet Charging time: 3 hours Usage time: 30 days List of packages: 1 x Anti-bark device 1 x do charging cable 1 x Screw Bag 1 x User Manual