AUTOMATIC AND HUMANEAnti Barking Device is equipped with the latest bark sensor system, which can automatically stop the dog barking, more convenient than manual bark control devices and safe for humans and dogs. 3 ADJUSTABLE FREQUENCY MODESThe first mode is audio mode, which emits a variable frequency of 10 to 16 kHz, suitable for small or sensitive dogs. The second mode is the first-level ultrasonic mode with a frequency of 20 kHz, suitable for docile or medium-sized dogs. The third mode is the second-level ultrasonic mode with a frequency of 25 kHz, suitable for playful or large dogs. You can turn on a low frequency to let the dog adapt, and then adjust it to a high frequency to stop barking. DESCRIPTION OF THE ANTI BARKING DEVICEWhen the Anti Barking Device detects excessive barking, the ultrasonic transmitter will be activated, at which time the Anti Barking Device will emit a high-pitched and safe ultrasonic sound (can be heard by dogs, but not by humans). The dog will stop barking when stimulated by the sound. The Dog Bark Deterrent is safe and effective for dogs of all breeds and sizes. SAY GOODBYE TO BARKINGDog Bark Deterrent can effectively stop dogs from barking and does not require a collar. WATERPROOF LEVELThe Dog Bark Deterrent is designed for outdoor use, durable and waterproof (IP45), you can hang it on a tree, place it anywhere in the house or yard.