I have three of the Dog Silencers now. I have two German Shepherds and neither of them bark. They are trained to growl if there is a need to alert me. And, they will quiet when commanded. So, when a new neighbor moved in next door with two untrained rude dogs that bark every time a breeze blows a blade of grass something had to be done. These two dogs would bark absolutely non-stop; all day and all night. We couldn’t even sleep peacefully. I purchased one Dog Silencer Max first and both dogs immediately took notice! I purchased two more because the dogs moved to a different area of the yard. So now I can reach the dogs wherever they go when they are beside my property and stop them from their incessant barking. It’s peaceful again! Thank you.