The Dog Barking Deterrent Devices are highly effective in controlling dog barking. They emit ultrasonic sound at 25kHz, which is above the hearing range of humans but easily grabs the attention of dogs. This makes them feel uncomfortable and helps stop their bad behaviors like barking, digging, and fighting. By pressing the button, you can teach your dog that their bad behaviors will result in an uncomfortable experience. These devices come with 3 different frequency waves to prevent dogs from getting used to a single frequency. They can emit ultrasonic sounds with stable frequency, undulating frequency, and irregular frequency sound waves. By choosing different waves, you can avoid dogs becoming desensitized to a simple frequency, ensuring long-term effectiveness in training. The Dog Barking Deterrent Devices are rechargeable and feature a low power light indicator. With a 300mAh battery, they can be fully charged in just 1 to 2 hours, providing approximately 12 days of regular use. This saves you the hassle and expense of constantly buying batteries. When the power is low, simply push the function button and the indicator will turn red, letting you know it's time to recharge. Key Features: Emits ultrasonic sound at 25kHz, above the hearing range of humans 3 different frequency waves to prevent dogs from getting used to a single frequency Rechargeable with a 300mAh battery Full charge in 1 to 2 hours Approximately 12 days of regular use Low power light indicator Helps stop bad behaviors like barking, digging, and fighting Teaches dogs that bad behaviors result in an uncomfortable experience