A unique perforated neoprene-like material that retains heat, but not water. The perspiration generated by exercise flows through the AIRPRENE to keep the skin dry and comfortable. AIRPRENE eliminates excessive heat build-up associated with neoprene. Medial and lateral hinge stays provide excellent support. Enclosed tubular donut buttress. Hyperextension stops at 170°. Easy removable hinges for custom fitting.