GOT QUICK RESULTS
I kid you not, this 'bird house' device did the trick within three days! Situation: Beach community with decks about 25' apart. The neighbors 'Heinz' variety barked at everything; with the owner offering little assistance & with no positive results! Well the dog must have a high IQ because his barking tapered off almost immediately!!!

Be quiet dog I'm sleepin!
Turn it on and dogs that barked for 30 minutes will usually quiet down after 5 minutes. Many restful nights now.

Shaking doggie
It definitely works because my 9 lb dog is barking much less. However, even on the lowest setting it scares my dog so much that she shakes uncontrollably for about an hour. It's still worth it though because her barking was unstoppable.

Beware of Fence
When this product arrived, we read the fine print on the box. It said that it needed to be located within 5 feet of the dog, with a clear path in between. Since our barking dog was on the other side of an 8 foot wood fence, the product was useless - and immediately returned.

Amazon did handle the return promptly and well.

Still have a barking bassett
I hate writing bad reviews, but this bark control is just a nice decoration on the outside of my house. It really did not for our dogs!