The effect of the collar was instantaneous, and its use over the last two years has been extremely limited. Infact I cannot recall when it was used last. We now own a happy and reasonably well behaved dog, which does not chase sheep or horses and will hold back from running in to game birds. He can roam freely off-the-lead without getting himself into potentially dangerous situations. Our second pointer, Pablo, is not so headstrong and has learned to respond to the whistle – without recourse to the collar – but by following Carlos….. the PAC electronic collar has done a great service to our dogs by making it possible to enjoy the freedom that their nature requires.