What is the Mueller Hg 80 Knee Brace with Kevlar? Ultra comfortable hinge free knee brace with closed kneecap. Features flexible steel springs that provide support for cartilage injuries, mild arthritis & collateral knee ligament injuries. When can I use it? Ideal for the stiff, weak or painful knee. Provides support for medial & lateral knee ligament & cartilage injuries, as well as the knee arthritis. Which size do I need? Fits left or right knee. Measure around the centre of the knee. If measurements indicate two different sizes, then choose the larger size. Small 30-35cm (12-14") Medium 35-40cm (14-16") Large 40-45cm (16-18") X-Large 45-50cm (18-20") How does it work? The flexible steel springs offer support & the stabilising double upper Velcro straps provide a customised fit for total support & comfort. Its unique non-slip strips prevent unwanted movement of the knee brace. This knee brace is completely neoprene free & has no raised seams & the inner lining is made from moisture wicking Hydracinn™ fabric. This means your brace doesn't get hot, sweaty & uncomfortable during sports. The flexible steel springs & stabilising patella buttress also have Kevlar protection for extra durability & the inner lining is completely free of neoprene & latex. It has an anti-microbial coating which prevents bacterial growth. This means your knee brace won't end up like the smelly one in the bottom of your rucksack, no matter how many times you use it.