• The anti-bark device is the most humane and effective way to stop unwanted barking. • Easier to use and safer than the electric dog collar. • Power on: Turn the knob to level 1, level 2, or level 3. • The blue light flashing means the device has been turned on. • Standby: the blue light flashes every 6 seconds. • Start working: the red light stays on for 3 seconds. • Low power: the red light starts flashing. • The maximum detection range is 10 meters. • It will not activate if the dog barks outside this range. • Does not work for dogs with hearing problems or aggressive dogs. • Recommended for dogs from 6 months to 8 years old. • Not recommended for two or more dogs barking at the same time. • Make sure the bark controller is facing the dog within the unobstructed range. • Change the frequency every 7-10 days to avoid resistance. • Includes: 1 bark control device, 1 USB charging cable, 2 mounting screws and anchors, 1 user manual.