Kenox Dog Leash Harness Adjustable and Heavy Duty Denim Dog Training Walking Leash Collar for Large/Medium/Small Dog Small: 11.8-17.7 inches (Pet weight: Within 250 ounces) Medium: 13.8-21.6 inches (Pet weight: Within 700 ounces) Large: 15.8-27.6 inches (Pet weight: above 700 ounces)