These spray citronella at your dogs snout to stop them barking. My dogs aren't the brightest but even they learned not to bark in a day. Not to be left on the dog unsupervised or when not home but great for training your dog quickly not to bark. I only had to put the collar on each of them for a few hours a day for a week and after that I just put the collar on switched off if they go back to their barking ways. I also only used outside as they went mad when someone walked by the gate or when birds landed on the wall. In the house they both still talk/bark and are as noisy as ever but then they have never worn the collar in the house.