My dog has such high drive he just powers through getting electrocuted. We bought the model for training (higher power). On max setting he completely ignores it. I was holding the button because he was barking at someone walking by the house. He sounded like a robot with that thing shocking his neck while he was barking. He basically just ignored it. We didn't use it for very long.
RE: Invisible Fence System For Pet Containment: The Technology & How it Works (Research-based)