The instant I clipped on the leash, I saw the difference. We have a 1 year old 80lbs Golden retriever and we were so discouraged everytime we went walking. He pulled constantly. I was scared when my pregnant wife had to take him out while I was out working. But since yesterday, we enjoy your walks. We don't have a double leash, because didn't read the description properly and I thought it was included in the box, but do not worry, it will work like a charm anyways. The only thing I regret is not buying this sooner!