Whenever it detects a loud noise, it activates and emits ultrasound. It doesn't necessarily have to be barking. Even a clap in front of the sensor will activate it. It does the job, but not miracles. The dog, who used to bark 20 times, now barks 10 times... Finally, in order to function properly, it needs to be placed at a close distance from the dog, maximum 3-4 meters.

It did absolutely nothing - maybe even made the situation worse.

If you are bothered by a neighbor's dog in the garden, this is not the solution.... If you tell your neighbor that their dog bothers you, you will make a big mistake, unless you are very good friends.

Good luck!