I had the older 2 collar model for about 7 years and those collar on/off buttons finally wore out and would no longer work. My 2 Great Pyrenees mix sisters were trained on the older model which had the tone function. I added a third collar few years ago when I adopted anotherdog( not a Pyr) . That newer collar still works) . It worked well for him as well. That 3rd dog has since passed and I adopted a purebred Pyr so I ordered the full set for 3 dogs . I mainly use them to call them back in the dark but only the vibrate function . I was skeptical as to whether the newest Pyr could be trained on it since she was a year old. ( my sisters were trained as pups ) but the vibrate did help her with recall. I also have invisible fence as well on 7 acres. It's a great system when used with proper training . My purebred is more stubborn as far as wanting to come back so I have stopped using the collar on her.