This device was recommended to me and I cannot say enough good things about it. It's very effective and broke my very loud, large lab of barking in just a few days. I agree with previous posts that you must put a verbal and/or hand signal to make this work long term. Now, I just have to tell my dog "no bark" and he will stop. We have found other uses for this device such as breaking up play that has become too rough between our dogs.