Specification: Product Name: Sonic Bark Deterrents Power: USB Input Voltage: 3.7V Input Current: 40mAh Battery: 3.7V 1500mAh ICR 18650NH Waterproof IP Rating: IPX4 Sensor: Sound Detection Sensor Distance: Up to 25ft Ultrasonic Frequency: 15KHZ-30KHZ How to use: Power On: Adjust the knob to level 1, level 2 or level 3. Blue light flashing means the device has been turned on. Stand-by: The blue light blinks every 6 seconds Triggered by dog bark and start working: Red light stay on for 3 seconds. Power low: Red light starts flashing. It means the device need to be charged or it will stop working. Adjust the level of frequency by turning the knob: Level 1: Ultrasonic Frequency 15-30KHZ,apply to large naughty dog. Level 2: Ultrasonic Frequency 20KHZ, apply to docile dog. Level 3: Ultrasonic Frequency 30KHZ, apply to small dog. Packing List: 1 x Receiver 1 x USB Cable 2 x Mounting Screws and Anchors 1 x User Manual Tips: Different dogs may be sensible to ultrasound of different frequency bands. Please turn the knob to test different frequency bands to obtain the best results. Using the same Ultrasonic frequency at the same dog for 10 days or more is not recommended. The dog may have resistance to the same ultrasonic frequency. Please change the ultrasonic frequency every 7-10 days. Please check the battery power every month, charge it if the power is too low (red light starts flashing).