The Perfect Training Tool: Anti-barking device the ultrasonic wave of the flashing flashlight is effective on dogs and can painlessly change all annoying, unsafe behaviors under full control in 3 seconds,in Deterrent mode, it will emit a powerful ultrasonic wave while flashing the flashlight,suitable for indoor and outdoor use. Hearing Sensitivity:just about ~3% of dogs(＞50pounds) do not respond to the device,we refuse to stop short of 100% effectiveness。 The average human hearing range is between 20Hz and 20KHz, while dogs have even more acute hearing, able to perceive sounds in the range of 15Hz to 50KHz. Our ultrasonic barking controller emits ultrasound at 25-30KHz, which is a frequency that is highly coordinated with your dog. This device provides a safe and effective solution for dog training and barking control. User-friendly: Our barking deterrent includes a flashlight mode for walking dogs at night.Its design characteristics are bright at night, clear lighting, not afraid of the night, there are independent buttons.