Alpinestars Reflex Knee Protectors. Suitable for MX, OFF-Road, Street, Track, Supermoto. Protect your knees man, you'll thank us later. Asymmetrical design for superior fit. Impact resistant polypropylene structure. Biofoam padding for comfort and cooling. Adjustable Velcro strap system. Extended panel along inner side of knee for additional safety. Vented panels reduce the buildup of heat. Alpinestars Reflex Knee Protectors.