1. Three Adjustable Modes: There are 3 adjustable modes of the barking control device low, medium, high, 15KHZ (low level) suitable for small dogs, 20KHZ (medium level) suitable for gentle dogs, and 30KHZ (high level) suitable for large and naughty dogs. 2. USB Charging: Our dog bark deterrent device features a convenient micro USB port for simple charging. Make sure to fully charge it before installation, which takes about 5 hours and lasts up to 30 days. 3. Easy To Use: The barking dog deterrent is small and lightweight, easy to install, you can easily install it on the dog house, fence, garden fence, table or tree, etc. The sonic bark deterrent is placed indoors for use or carried with you during outdoor activities. 4. Harmless Safe for Humans: Safe and Friendly Dog Barking Silencer: Our anti barking device utilizes ultrasonic technology to gently discourage excessive barking without harm. The ultrasound emitted is customized specifically for dogs, and humans can't hear them, so they have zero negative impacts on us.