Description Features: Pet-Friendly Anti-Barking Device: This ultrasonic bark control device works by sending a steady frequency of sound that only dogs can hear, preventing barking and calming dogs. No irritating odor, no electric shock, anti-barking only works when the dog barks. Bark repellents are hearing-safe for humans and dogs, and are great for creating a quiet space for dog lovers and deterring unwanted behavior. EFFECTIVE FOR DOGS OF ALL SIZES: Ultrasonic bark repellent with 3 adjustable sensitivity and frequency levels (15-30 kHz for large, playful dogs; 20 kHz for educational dogs; 30 kHz for small dogs) , to prevent dogs of different sizes from barking easily. Adjusting the frequency weekly can maintain training results. Easy to use: This rechargeable dog barking control device with LED indicator light is easy to use. The indicator light flashes blue every 6 seconds when you are working on 3 different levels; the red light stays on for 3 seconds when the barking sound is triggered; the red light flashes when the battery is low. OUTDOOR AND INDOOR USE: The IPX4 rainproof human bark device and portable hook can be easily hung on trees, walls or fence posts. But when it rains heavily, it is best to bring it back to extend its life. The ultrasonic dog device can be placed on tables, walls and shelves with a height of more than 1.5 m, and can be adjusted more effectively for barking, digging, fighting, etc. Material: ABS Packing list: 1* Anti-barking device control 2* Installation screws and anchors 1* USB charging cable 1* User manual