Air-Stirrup® Ankle Brace 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. - See more at: http://www.djoglobal.com/products/aircast/air-stirrup-ankle-brace#sthash.nVCKQvH6.dpuf