Of course, in order to attach your dog to a leash, you will
need a collar or harness. Like leashes, make sure the collar is rated for the
dog's size and weight, otherwise a large dog can rip or break a collar no
matter how sturdy your leash is. It is important to make sure a collar fits
properly; you should be able to slide two fingers between the collar and the
dog's neck.
When do you need a harness instead of a collar? If your dog
regularly escapes from his collar or you feel he needs a heavier restraint, a
harness may be right for you. In addition, if your dog has a very small head, a
collar may not fit properly and a harness may be preferable.