Personally i advise against a harness, it plays to a boxers pulling power and could potentially (depending on the dog) create a bigger issue while walking then help the situation. Reese had a big time pulling problem and we used the Gentle Leader, we corrected the problem and have worked endless hours with recall. now she is off leash when going to the bathroom, and when we walk she only pulls if she sees a cat that she wants to "play with" or if she sees a person. We still us the gl from time to time just to help reinforce good walking. I do formally believe it needs to be used as a training tool to better the dogs performance while walking-the gl is not a fix-it-all tool.