Alpinestars Youth Bionic 5S Knee Braces - Black/Red Innovative hybrid frames are constructed from a flexible composite over-injected with a high performance fiber reinforced polymer which provides optimal structural integrity and support while being ultra-lightweight and adaptive Slim ergonomic design for riding comfort during dynamic movement Extremely stable slim-design four-point hinge system perfectly follows the articulation of the knee Lightweight and highly ventilated knee protector offers strong impact force dispersion and absorption while ensuring maximum coverage area in all riding positions The frame system reduces the risk of sustaining injuries to the medial and lateral collateral ligament, the anterior and posterior cruciate ligament and the lateral and medial meniscus