LEATT X-Frame Knee Brace Men, WomenInjected Carbon Composite Frame Asymmetrical Hinges 40% slimmer inner hinge for superior bike feel Metal geared outer hinge for precise movement and durability Reduction of forces to limit knee injuries: ACL, Meniscus and MCL Certified as medical device: EU CA014741,USA FDA 10048761 CE tested and certified as impact protection: Knee EN1621 1 Hyper extension limitations 5, 10, 15 and 20 for ACL injury reduction Fixed hyper flexion stoppers for meniscus