AIR-STIRRUP? Ankle Brace is anatomically designed semi-rigid shells lined with the patented Duplex? aircell system for support and graduated compression during ambulation. The compression promotes efficient edema reduction in addition to helping accelerate rehabilitation of ankle sprains. Wearing the brace enables to continue patient with daily activities while recovering from your injury. This is a unique, patented dual air cell design. Adjustable heel pad for proper fit and greater compliance.