If you have a dog then switching over to a harness could be one of the best things that you can do for them. With a traditional collar and leash the dog can experience pain, coughing, damaged neck muscles and poor behavioral control. However, by switching to a harness and leash your dog will find it harder to pull but much easier to breathe and be guided by your pressure changes on his torso.
I have made a great list of harnesses here that you will really enjoy. All of the harnesses selected are fine for small to xx-large dogs as the ranges have different models that are easily adjustable to fit your dog's unique shape.