Halter Harness for Dogs

The Halter Harness from Aspen Pets is supposed to stop dogs from pulling when walked on a leash. Apparently, I bought this around 2004, but never used it. The packaging has been opened, but the harness has never been used. This is supposed to work with any standard dog collar, and the diagram to show you how to do it is on the back. This harness is red, and a size medium. There is no sizing guide to help you determine if a medium will fit your dog.