Holy cow these things work. Our dog is one of those dogs that barks at E-V-E-R-Y-T-H-I-N-G... We got one of those ultrasound things at first and it worked at first to curb the barking. But after a while he got immune to it. Finally got one of these anti barking collars that beep and vibrate when it detects barking. I kid you not... literally in one day the problem was solved. We've had it now for several weeks and its still effective. He's like a totally different dog now. Should have done this years ago... anyone else with a dog with barking problems, definitely recommend it.