MEDICALLY CERTIFIED PROTECTION We learned a lot from developing our C-Frame and X-Frame knee braces, and we recognize the need for a great knee brace that won't break the bank. Not as stiff as the C-Frame or X-Frame, but a good chassis made from glass-filled nylon for comfort and a Carbon Injected knee for that rigidity which reduces the ACL, Meniscus, and MCL injury risk. The Z-Frame is also CE certified as a medical device and as impact protection, maybe it's time to get rid of your knee protectors and get yourself a knee brace? Next step up is the X-Frame for a stiffer chassis and our top line cage type brace or the C-Frame Pro Carbon knee brace, if you are looking for a single sided hinge. Injected Composite chassis Slim hinges for superior bike feel Reduction of forces to limit knee injuries: ACL, Meniscus and MCL Aluminium hinge covers for rigidity and endurance Certified as medical device: EU CA014741 USA FDA 10048761 CE tested and certified as impact protection: Knee EN1621-1 Hyper extension limitations 5º, 10º, 15º and 20º for ACL injury reduction Low-profile shin bone pad for excellent boot fit Comfortable, easy-fitting and low-profile strap system Customized fit with interchangeable hinge padding sizes Sizing: S - M - L - LX - XXL Plastic Free Recyclable Packaging 5022121900 (S) 5022121902 (L) 5022121903 (XL) 5022121904 (XXL)