Bests & Worsts Reviews from Amazon

...and that's not a bad thing, when you have more than one dog but only one you're trying to shut up. You just need to hope you get the right dog. Apparently it has a frequency that only some dogs can hear, hence the polar opposite 1-star and 5-star reviews. I bought this with only the Yappy Dog Who was About to Get Shipped to the Pound in mind. Halfway home, it occurred to me that it would also freak out the Perfect Angelic Quiet Old Faithful Dog Who Never Barks (Three Cheers for Retired Racing Quiet Greyhounds! Woo-hoo!) I got it home and carefully took it out of the package, intending to return it if it bothered Quiet Dog. Yappy Dog was outside, and I tried it with Quiet Dog, who can hear kibble being poured into his bowl from 500 paces, right next to me, awake (important to mention, because he rarely is). No response whatsoever. Not an ear flinch, not a crooked-head look, nothing. A little later, I tried it again when he was asleep. Nothing. So I assumed it was just plain not very effective, so I still intended to take it back. Soon after, Yappy Dog started the behavior I was hoping to curb. So I went out and gave it a try. You would have thought I'd zapped her with a cattle prod. Now our lives have changed. We are also able to use it for other undesirable behaviors, like pulling on lead, relentlessly pestering Quiet Dog, and nipping at heels and play-biting hands (she is a year-old Australian Cattle Dog mix who was apparently tied out for her entire puppyhood, then abandoned with inevitable serious behavior issues ). With a little beep reinforced with a "No!" , we were finally able to stop behaviors when previously just at "no" wasn't enough. I'm pretty sure just a day or two with the "beeper" will be enough to turn her around. So my recommendation would be to take it out of the packaging to see if it will work on your dog. If it does, it really will. If it doesn't, it really won't.