Add me to the growing list here of people who swear by this product and are amazed at its effectiveness. It really does work, so much so that I felt compelled to tell others.
Like other reviewers, I bought the Dazer in desperation after all other methods had failed to stop my neighbors' two Schnauzers from barking at me and my children every time we tried to use our own back yard. When I first used the Dazer on them, the dogs actually stopped mid-bark and looked at me as if I had just called them Chihuahuas. When they started to bark again, I Dazed them a second time and again, they stopped instantly. I then gave the now-silent and clearly befuddled mutts one final shot of ultrasonic goodness for good measure (heh heh), at which they turned and scurried off into their house - not in pain, but clearly annoyed at whatever sound the Dazer puts out (humans cannot hear it, nor can my two elderly dogs).
The mongrels and I repeated this scenario for two more days after this, and that did the trick. Now when anybody in my family goes into the back, they either run off or ignore us completely. Oh, they still bark sometimes, but not at us. Like John Wayne (as one reviewer put it so well), I keep the Dazer clipped to my waistband just in case I need to remind them what it sounds like. I might even have done so once or twice, but that cannot be confirmed.
I don't know if the thing works on all dogs, or if it stops a charging dog, and I hope never to find out. I wouldn't rely on the Dazer or any other device to protect my children from an attacking dog, anyway, as Mr. Schinzer below might. But I know this: the Dazer has made my back yard a fun and QUIET place for me and my family to enjoy once again.
Now, if it only worked on loud people...