Review on BIG DEAL Anti Barking Device: Stop Dog Barking Indoors & Outdoors with 50 Feet Range - Safe Training Tool for All Dogs by Stephanie Johnson

I was very surprised how small this thing is but how effective it is! In the photo I've circled it in red to show how invisible it is. We have two large German Shepherds and I wanted to teach them not to bark when in the kennel. I tried the lowest level first and sure enough, when the bigger one barked it stopped immediately and the other bowed his head in confusion, but neither panicked or feared. A little later our self-confident red-striped Chili ran in front of the kennel and barked at both dogs. So I took it to the next level, and since then I've sometimes heard a bark that's not followed by another. The thing works!