Mueller Hg80 Hinged Knee Brace Mueller Hg80 Hinged Knee Brace features exclusive HydraCinn fabric that is non-neoprene, moisture wicking, breathable, and antimicrobial. Inner grip strips and upper strapping system help prevent brace migration. Patented triaxial hinges provide maximum protection with near-normal knee motion. Tibial containment system features a custom secondary shell with stabilizing patella buttress and rear support strap. Sizing: Measure circumference of knee at center of joint. Sizing: Measure circumference of knee at center of joint Sm. fits 12"-14" Med. fits 14"- 16" Lg. fits 16"-18" X-Lg. fits 18"-20"