We purchased this system over a year ago. It worked great at first but the dogs have begun to run through the IF almost every day. They don't seem bothered by the shock, a slight yelp and then they're off! It has become very frustrating and also upsetting to worry about them getting stolen or worse, hit by car. I have spoken with others who have the system and rave about it, but my vet says that sporting dogs, like our beagle/spaniel mixes, cannot resist the urge to run and will take the punishment of the shock in order to do so. I am disappointed this didn't work for us because we are now going to have to spend additional money building a fence to contain our dogs.