Turn this on and set it somewhere in your home or backyard where you want to deter barking. Emits a sound that is irritating to dogs when they bark and helps train them to stop. You can use it on neighbor’s dogs as well if your yard is close enough. I have read that not all dogs are deterred so you won’t know til you try it. Takes a 9v battery which is not included but I did test it before listing it. In used condition.