I have a stress-prone, fearful mixed breed dog from Romania. It reacts anxiety aggressively to strangers and afraid in buildings / streets to run. The collar has a calming effect on her, or it can come down to excitement pretty quickly. It is done not surprising, but a small, fine effect, makes the training easier. In addition, she gets special food supplements to their anxiety and the whole package makes our lives at the time really pleasant. However, they sometimes interfere with the collar a little bit - it is not used to collars. I would again at any time to buy, a friend and I will offer my second dog also. (It makes sense to let the dog nose first and see if he shuns. If the collar first created, the dog can not escape, it should be unpleasant to him.) When similar problems is always worth a thyroid examination with a specialist !!! Vet!