The Volas Pet Dog Rear Leg Injury Recovery Support Harness listing says it aids hind-leg recovery and mobility support, uses strong denim and flexible elastic webbing, has an adjustable fit for various dog sizes, is comfortable for everyday walks and offers secure assistance while allowing free movement.
Those are product-page lines, not a diagnosis or a recovery plan. Ask a veterinarian about your own dog. The first photo shows a wide band around a dog’s midsection, not a labelled rear-leg sling.
See the Volas dog harness in Pets.