I bought my first Dazer 20 years ago. It worked on every dog. Hundreds. Then I lost it. Bought a new one about 5 years ago. It worked on NO DOGS. Just thought I had a defective one, but the review you linked to seemed more like my second experience.

If you get a good one, it will work. The manufacturer admits that deaf dogs are immune (of course) and a small percentage of dogs become even more enraged by the sound.

I am soon going to buy another one directly from KII Enterprises and see what happens. My first unit worked so good. EVEN through a plastic bag.

Currently I have been riding road bikes so much that I use a full sized frame pump as a club. Dogs seem to understand when I raise up to "go all baby seal" on their arses.