this is great tool for off leash control  http://www.youtube.com/watch?v=OU2T_zzLKCQ and a must have for dogs who are deaf http://www.deafdogs.org/training/vibratrain.php I will be posting a video soon on my youtube of a deaf American Bulldog working with the collar if you have a youtube account subscribe to my videos!! I don't get on here much but if you have any questions feel free to ask them via the youtube! thanks heres a couple others teaching a resit http://www.youtube.com/watch?v=hgO9vbYlB1w two dogs together http://www.youtube.com/watch?v=6fLy9lMHsUM Great dane and St Bernard http://www.youtube.com/watch?v=jCcuDg4iGCs