I have used the Pet Safe containment system for 3 years and it works great!!!! I have 3 big dogs, a boxer, a chow and a lab and they all respect the boundries. It took people walking down our road a while to figure out the huge running, barking dogs would stop before the road. It is great, because not only are the dogs allowed more freedom in a safe way, but no one is going to come up to my house without having to go through the dogs. The system explains how to train them in the beginning. Set up the system and put the collar on your dog with his regular collar and put a leash on his regular collar and walk the perimeter. When your dog goes over the line he will hear a beep from the collar. Pull him back towards you and praise him. After several times, you may let him go far enough (on the leash) to get shocked, then pull him back to safe zone and pet him. I only had to do this a few times and they all got it. Then just be sure you have extra collar batteries on hand so when it starts blinking you can change it right away. E-mail me if you have other questions. Good luck, Denise