What is it?

One or more metal struts which extend from the top of the calf to a tube which fits into the wearers footwear via a pin (spur). The strut(s) is attached to a metal band which encompasses the posterior (back) half of the leg and is covered with  padded leather which extends around the front of the leg and is secured with a velcro strap. The strut position will depend on the condition being addressed.