No ultrasonic stable sound output comes first: If the human ear could hear it, it would not be ultrasound. If you can't hear the whistle, how can you be sure that the whistle works? And the ultrasonic whistle is not suitable for all dogs. Some dogs do not even blink with the eyelids when they hear the so-called ultrasonic waves. Have fun with your dog outdoorsEliminate complex tone adjustments and make sure that every dog can hear the whistle. Great for calling the dog back or preventing him from being wrong. FUN STOP DOG BARKING BY TRAINING THE DOG YOURSELFWouldn't it be funny to get your dog to stop barking by training it yourself? When the dog constantly barks, try to trigger a stop command with the whistle. Give the dog this command when you train the dog constantly. Reward the dog when he adjusts and pants. Patience is the true bond between you and your dog: Some dogs may feel very uncomfortable with ultrasound. The principle of ultrasound to stop dog barking is to use ultrasound to make dogs feel uncomfortable. Anti-bark spray for dogs would be better, but can dogs be so cruelty? Two-in-one design: the dog whistle is used to give commands, the dog clicker is used to give the dog a confirmation after completion of the command.