Since 1978, the Aircast Air-Stirrup Ankle Brace has been the "standard of care" for the functional management of ankle injuries. Each Aircast Ankle Brace features anatomically designed shells lined with the patented Duplex? aircell system. This exclusive system incorporates two pre-inflated overlapping aircells, distal and proximal, that provide support and produce graduated compression during ambulation. The compression promotes efficient edema reduction in addition to helping accelerate rehabilitation.