I have a very annoying barking GSD and i wanted a device that would automatically correct his barking without me having to use a remote. So I bought this.At first, I read the instructions, and it said to test the device by "barking" into the device using your voice. It never worked. But I strapped it onto my dog nonetheless. My dog's barking SOMETIMES triggered this device, and it was never consistent.So I got in touch with the seller and they recommended sending me a different product, I assumed a remote shock collar, which I did not want because it meant I had to manually trigger the device every time my dog barked. I wanted to try the same prduct again because the reviews were so good and I believed I just ended up with a defect.So they sent me another replacement, and this time it was triggered by my voice !!! just as it should. I "barked" into the device, and it triggered the device better (not all the time) than my first one. And it definitely works on my dog.The improvement of my dog is night and day.For users who are wary of shocking their dog, I don't use the shock feature, just beep and vibrate, and it still corrects my GSD. So if you are worried about shock feature, you DO NOT have to use it, which is good since it gives the user an option.