- Walking harness with a leash for cats and dogs (small breeds of dogs and medium breeds, puppies) for walking. The vest harness replaces the collar. A harness vest is more convenient and safer for your pet. The harness does not put pressure on the dog's neck if the leash is pulled, unlike a collar. There are reflective stripes. Adjustable straps allow you to customize the size of the harness to suit your pet.