With a standard collar, the leash tension caused by a pulling dog is applied directly to the dog's larynx/trachea area causing discomfort for the dog as well as restricting the airflow through the windpipe. This is the reason why dogs "hack" when they pull on their leash. The Sporn Pull-Control patented design redirects the leash tension to the area behind your dogs front legs, a sensitive area where the slight pressure of the Pull-Control restraints will stop your dog from pulling without discomfort. The restraints also come with the fabric Sherpa Sleeves which provide comfort for all dogs. To fit neck size of 9 to 12 Inch