Mueller Hg80® Premium Knee Stabilizer Extreme comfort and adjustable support. The Hg80® Premium Knee Stabilizer is simply the most comfortable brace you’ll ever wear. Supportive steel springs support both sides of the knee, yet still allow leg flexion and extension. So you get the support you need without hampering your flexibility. Improved Mueller-exclusive HydraCinn® fabric is a high-performance, moisture-wicking material with an anti-microbial barrier.* Recommended to help control sublaxating patellas and to help support stiff, sore, or unstable knees.