This harness is great for pets that are physically challenged or have structural limitations and can be used on amputees. Designed to help cats and dogs suffering from arthritis, hip dysplasia, spinal trauma and general fatigue it can be used on animals that have nerve damage, need soft tissue management, sporting dogs, and police dogs. It is also useful for pet owners or handlers in avoiding personal injury. The Rear Harness is designed to fit male and female pets. Medium will fit dogs measuring 38-53.5cm (15-21”) around the abdomen in front of the legs and 15-30.5cm (6-12”) around the back leg where it meets the body. Medium only has one handle unlike the harness pictured, which has two.