The Seirus Hyperflex Nuclear Knee Support is a breathable neoprene brace with a Hyperflex Lycra insert. This knee brace features technical locking, dual pivot, metal hinges to help prevent hyper-extension. It has a padded patella locator to relieve pressure and Velcro adjustable straps. This knee brace is great for snowboarding and telemark skiing and other sports. To determine your size, measure your thigh just above the knee cap and use the sizes indicated.