The harnesses is an "H" style that attaches with velcro. The front legs of the "H" go around the ferrets neck and the back leg of the "H" goes around the ferrets tummy just behind the front legs. This harness adjusts from the size of a quarter to the diameter of a soda can to fit just about any size ferret. The harness also includes a bell so you can keep track of your ferret should you wish to let him play with just the harness on.