As soon as I got my pet gentle, it had an immediate effect on my collie/labrador cross. It not only stops him barking, but also distracts him from other unwanted activity. Today, he got in to a field of sheep. He was charging around after them and was not responding to my calls that usually work. I was so worried and scared that the farmer would see and come and shoot him. But I got in to the field, approached him and pointed the petgentle at him, pressing the button. He stopped, sat down, and then came to me looking very sorry. I then him, User's recommendation: This product clearly works well for some dogs, and some dog breeds, but not for others. But I would say its a small price to pay, to find out.