The truth is that it works. So, for all those who say it doesn't work, I believe they simply haven't followed the instructions on the leaflet. If the dog has thick fur, it should be trimmed to ensure contact with the collar. Also, the device should be placed underneath the dog's neck, it doesn't need to be too tight but minimal contact is enough. 1. I was afraid to use it from the beginning because, as you can understand, we're talking about electricity and I didn't know how much it would hurt. We tested it on ourselves and it's like when someone "performs magic and touches you with electricity," it's exactly the same, minimal, but when you feel it unexpectedly, like how dogs get scared and stop barking. 2. In the initial phase, there is a sound, and if there is a second bark within 30 seconds, then it's the electricity. Our dog only felt the electricity once, then understood that after the sound comes the electricity and stopped barking. 3. We don't use it constantly. We put it on, it barks, hears the sound, then realizes it shouldn't bark and stops, so we take it off, and usually it doesn't continue. If it starts barking again later, I put it back on for a little while until it barks again, and then take it off. I don't leave it on because first, it's not very comfortable for the dog to lie down, and also because it says it can be accidentally activated by a movement, so I don't want to risk scaring it for no reason. That's it. Personally, it saved us because it was constantly barking on the balcony, and obviously our neighbors didn't like it. Now I leave the balcony open and it's quiet.